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  • richardmitnick 2:02 pm on January 18, 2019 Permalink | Reply
    Tags: , , Seismic swarm hits Hayward Fault: What does it portend?, , temblor   

    From temblor: “Seismic swarm hits Hayward Fault: What does it portend?” 

    1

    From temblor

    January 17, 2019
    Jason Patton, Ph.D.

    The San Francisco Bay area is earthquake country. Historic and prehistoric evidence for earthquakes here informs us about the possibility of future shakers. On the Hayward Fault, we have an idea about their upper limit on size, but we don’t know when they will occur. The swarm in progress, with an M=3.4 quake on January 16 and today’s M=3.5 quake near Piedmont and Berkeley, are but one way to peer into an uncertain future. Ultimately, they remind us to be prepared to confront potential disaster.

    Earthquake swarm highlights our earthquake history and our earthquake future

    People in northern California have been in the midst of an earthquake swarm along the Hayward fault. Over 6,000 people reported observations of an M=3.4 quake and so far, over 4,000 have reported to the USGS “Did You Feel It?” website for the M=3.5 morning quake today.

    One may think that these quakes are small, so why do they matter? Why should I care?

    Prior to the 1906 San Francisco earthquake, the 1868 event was called the Great San Francisco Earthquake as the damage was widespread across the entire region. According to the USGS, the Hayward fault has the highest chance of rupture for all faults in the bay area, which is why Temblor’s Earthquake Scores for homes near the fault are among the highest anywhere in the U.S.

    The USGS, California Geological Survey, and other stakeholders like the California Earthquake Authority (earthquake insurance) have teamed up to help people learn about a probable repeat of the 1868 earthquake. Learn more about the “HayWired Scenario” on this website.

    Below is a map that shows how the shaking intensity may be across the region in a scenario M=7 quake, similar to the 1868 event. (Hudnut et al., 2018).

    2
    Shaking severity from an hypothetical earthquake on the Hayward fault.

    Last year there was an M=4.4 earthquake in the Piedmont area, which is pretty close to the swarm of quakes that hit in the past 2 days, although unlike today’s quake, it was not on the main strand of the Hayward Fault. Along the Hayward fault, sometimes there is a series of earthquakes that all have similar magnitudes (a swarm) and sometimes there is an earthquake that is larger than the others (a sequence). According to Dr. Peggy Hellweg, Project Manager for the Berkeley Seismological Laboratory seismic network, “typically what we see on the Hayward fault are sequences” and that there is a sequence about every 2 to 5 years, over the past 20 years. Here is a blog post from the Berkeley Seismo Blog for a quake in 2017.

    Sadly, the USGS cannot respond to press inquiries due to the U.S. Government shutdown. However, we can use the USGS earthquake catalog to learn about the recent history of earthquakes along the Hayward fault (see map below). Within 2 km (1.2 mi) of the fault trace, on average, there are quakes a little less than once a year. Quakes right in the Hayward Fault trace are rarer, they strike about once every 3 years. One sees no obvious migration of these quakes with time, which makes it impossible to identify if the fault is getting ready for a “Big One.”
    3
    Hayward fault earthquake locations since 1985.

    For now, we don’t’ know if this swarm will lead to larger magnitude earthquakes. However, we do know that as time passes, the fault gradually stores more elastic energy and this leads to an increased chance of an earthquake.

    There is lots much we can learn about what happened in past earthquakes so we can prepare for future earthquakes. We recently reviewed what we learned over the past 25 since the 1994 M=6.7 Northridge earthquake here. Note the similar earthquake magnitude for the Hayward and Northridge earthquakes.

    The Hayward Fault is HayWired

    The Hayward Fault is unusual. Part of the Hayward fault is creeping aseismically (moving side by side without earthquakes) and part of the fault is locked (clamped together, storing energy that may be released during an earthquake). As the fault creeps, this places additional stress on the adjacent portions of the fault that are locked. The same is true for small earthquakes like the ongoing swarm, they add stress to the fault. A 100-km-long (60 mi) portion of the San Andreas also creeps, but the rest is locked. What makes the Hayward unique is that it exhibits both behaviors everywhere.

    Scientists have been studying how the fault stores this energy over time (e.g. Shirzaei et al., 2013), using satellite data and physical measurements of plate motion in the region. Shirzaei et al. (2013) found that both creep and these small earthquakes add to the stress on the fault and bring us closer to an earthquake.

    “We estimate that a slip-rate deficit equivalent to Mw 6.3–6.8 has accumulated on the fault, since the last event in 1868.” (Shirzaei and R. Bürgmann, 2013).

    Below is an updated plot provided by Dr. Roland Bürgmann, Professor of Earth and Planetary Science at U.C. Berkeley. This figure shows the fault surface at depth and the color represents how much of the fault is creeping (red = more creep). Drs. Bürgmann and Shirzaei have plotted the earthquake locations from the past decade or so, including from the current swarm.

    4

    Dr. Bürgmann wrote us this morning, “I’d like to point out that it was last year’s M=4.4 quake that made me sign up for earthquake insurance.”

    Ground Shaking, Building Collapse, Landslides, Liquefaction

    This is a short laundry list of potential damage that will probably face northern California residents during and following a future Hayward fault earthquake.

    Conclusions from the USGS HayWired Earthquake Scenario are sobering, however we can take action now to be more resilient in the face of this natural disaster.

    The mainshock will be damaging, but so will be the aftershocks. Building damage may exceed $82 billion (in 2016 dollars). As many as 152,000 households may be displaced, placing as many as 411,000 people on the streets (2000 census data). There may be 800 deaths and over 18,000 injuries. As many as 2,500 people may be trapped in buildings and more than 22,000 people could be stuck in elevators.

    As we mentioned in a report on the Sacramento-San Joaquin River Delta about potential levee failures, there may also be substantial damage to the water supply infrastructure as well. It may take as long as 30 to 210 days to restore water supplies for some of the counties in the bay area. Fires can be expected following a HayWired Scenario event. There may be over 400 fires, causing hundreds of additional deaths and contributing to an additional $30 billion in damages.

    There is a suite of natural hazards information available on the temblor app to help one learn the extent to which people are exposed to these hazards. Below is a map that shows the potential for liquefaction in the region. Learn more about landslides and liquefaction in our report from earlier this year here.

    5
    Liquefaction susceptibility from earthquakes in the SF Bay Area. The red dot is the M=3.5 earthquake felt this morning.

    Do you know where your home or workplace fits in earthquake country? Are you prepared? Check Your Risk in the Temblor app here.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States
    1

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

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  • richardmitnick 10:41 am on January 17, 2019 Permalink | Reply
    Tags: , , , , temblor, the U.S. government shutdown, What if the Northridge earthquake had struck today   

    From temblor: “What if the Northridge earthquake had struck today, on its 25th anniversary, during the U.S. government shutdown?” 

    1

    From temblor

    January 16, 2019
    Jason Patton, Ph.D.

    Ross Stein, Ph.D., Volkan Sevilgen, M.Sc.

    Twenty-five years ago, the M=6.7 Northridge earthquake caused enormous damage in southern California. Today people are far less insured, and the best estimates suggest that we would take a major economic hit if one like it were to strike the Southland today. The government shutdown would only compound the problems.

    What if the Northridge Earthquake Happened Today?

    The M=6.7 earthquake struck on a ‘blind’ thrust fault (meaning that geologists were blind to its presence). There are other blind faults in southern California that pose an equal or greater hazard to the economy and well-being of Angelinos, and despite being associated with earthquakes up to M=7.3, blind thrusts are notoriously difficult to identify. Learn more about these faults here.

    1
    Sylmar Overpass damage from the 1994 Northridge earthquake. Credit: USGS Public Domain

    Dr. Patricia Grossi from RMS, Inc., concluded that if an M=6.7 Northridge earthquake struck in 2014, it would cause up to $155 billion in total economic losses, comparable to that for Hurricane Katrina, which cost the nation $148 billion. But the insured losses would amount to only $16-$24 billion, or 10-15% of the total.

    What about other quakes in the Southland?

    An earthquake on the Puente Hills blind thrust fault, which runs beneath much of the Los Angeles basin including downtown, could cause over $600 billion in economic damages (Larsen et al., 2015). A recent M=5.1 earthquake on 29 March 2014 highlighted the presence of the Puente Hills and other blind fault faults in southern California capable of producing damaging earthquakes.

    The 1933 M=6.4 Long Beach earthquake ruptured the Newport-Inglewood fault, killing 120 and causing widespread damage estimated to be between $40 and $50 million (1933 dollars; Swift et al., 2012). If the 1993 Long Beach earthquake were to recur, the losses could be between $131 and $781 million, depending upon the earthquake size (given analysis in 2006 using valuation estimates from 2002; Swift et al., 2012).

    Many are familiar with the hazards from an earthquake on the San Andreas fault. If not, check out the video series “The Whistle.” The U.S. Geological Survey prepared a study of the impacts of an earthquake on the southern San Andreas fault (Jones et al., 2008). Using a computer tool developed by FEMA, they estimate that there may be as many as 1800 deaths and $191 billion in damages (in 2008 dollars and level of infrastructural development; Porter et al., 2011).

    2
    A large earthquake on the Puente Hills Blind Thrust Fault would strongly shake the most densely part of the Southland. The color gradients give the size of an earthquake expected over the period of a human lifetime (Bird et al., 2013). So for greater Los Angeles, a M=6.5-7.0 is likely.

    Do you know what your losses to earthquake hazards would be? Check Your Risk in the Temblor app here.

    Below is a map showing historic earthquakes in southern California (Hauksson et al., 1995). The spatial extent of the aftershocks correlate roughly with damage.

    3
    Historic earthquakes in southern California (Hauksson et al., 1995).

    The partial shutdown could make things worse

    During the government shutdown, the USGS is operating with a skeletal crew just sufficient to monitor earthquakes in California and around the world. However, no routine maintenance of its seismic and geodetic stations is being conducted, no buildout of the partially-completed Earthquake Early Warning system is being undertaken, no research is conducted, no publications are produced, no research meetings are held, and there is a press blackout.

    In the event of a large California earthquake, the USGS has been granted authority by the Department of Interior to resume operations with as large a staff as needed to protect life and property, and to collect essential data.

    Forrest Lanning, Earthquake Program Manager for FEMA Region IX (southwest U.S.), explained that if there were a disaster, FEMA would be mobilized in accordance with their mandate to respond to requests of disaster declaration from the state. Mobilized FEMA personnel would be given authorization to be paid for overtime under the Stafford Act, but the work leading up to this overtime would not be covered unless congress provided authorization. The FEMA Watch Center is required to be in operation 24 hours a day, 7 days a week. Staff at the watch center keep their eyes on media and other sources to determine if events may impact Region IX. They work with the NOAA Pacific Tsunami Warning Center and the USGS to monitor these potential impacts.

    But what would happen if, instead, there were a swarm of small earthquakes on a major fault, as occurred at the southern tip of the San Andreas in September 2016, or near the Calaveras Fault in northern California in February 2018? In fact, today, there was a M=3.4 quake followed by several others on the Hayward Fault, which last ruptured in a M~7 shock in 1868. Because of widespread damage, the 1868 quake was known as the ‘Great San Francisco Quake’ until it was dethroned in 1906.

    3

    When a swarm culminating in a M=4.3 shock occurred in September 2016 at Bombay Beach near the southern end of the San Andreas, USGS calculations and consultations led the California Office of Emergency Services to issue a week-long ‘Earthquake Advisory’ for the entire Southland.

    Seismic swarms are simply unchartered shutdown territory.

    Rate of Insurance Coverage is Down

    In 1994, 34% of Californians carried earthquake insurance. Today this is down to about 10%. Why is this?
    Costs are up

    The Northridge quake caused about $40 billion in damage in 1994 dollars (Eguchi et al., 1998), which was an unprecedented loss to the insurance industry, leading to a complicated response, with many insurers refusing to offer homeowner’s policies if they had to offer quake.

    The California Earthquake Authority was set up by the state following Northridge, to help provide insurance when most carriers refused to do so. The CEA is a privately funded, but publicly managed, provider of residential earthquake insurance. But because of a reassessment of the risk, all earthquake insurance premiums, as well as deductibles, rose.

    Out of sight, out of mind

    The more time passes following an event, the more rapidly people stop considering the potential impact of such an event if it were to recur in the future. This is especially true for earthquakes.

    In 1989, the large Loma Prieta earthquake devastated the San Francisco Bay area. The entire country responded in this time of need and the visual evidence of the impact of this quake was broadcast globally. People were aware of their place in earthquake country and this may have contributed to the large proportion of people who had earthquake insurance when the Northridge quake hit.

    So, the take away from this is that, depending on the costs of repairing expected quake damage to your home, you should consider earthquake insurance and seismic retrofit. Without economic resilience, we may crumble under the load, as the column did in the following photo.

    4
    Building damage from 1994 Northridge earthquake, the parking structure at CSU Northridge. Credit: USGS public domain.

    References

    Bird, P., Jackson, D. D., Kagan, Y. Y., Kreemer, C., and Stein, R. S., 2015. GEAR1: A global earthquake activity rate model constructed from geodetic strain rates and smoothed seismicity, Bull. Seismol. Soc. Am., v. 105, no. 5, p. 2538–2554, DOI: 10.1785/0120150058

    Eguchi, R.T., Goltz, J.D., Taylor, C.E., Chang, S.E., Flores, P.J., Johnson, L.A., Seligson, H.A., and Blais, N.C., 1998. Direct Economic Losses in the Northridge Earthquake: A Three-Year Post-Event Perspective in Earthquake Spectra, v. 14, no. 2, p. 245-264 DOI: 10.1193/1.1585998

    Grossi, Patricia (2014), Northridge Earthquake today could cost insurers $20B, Carrier Management, 20 January 2014, https://www.carriermanagement.com/news/2014/01/20/117897.htm

    Hauksson, E., Jones, L.M., and Hutton, K., 1995. The 1994 Northridge earthquake sequence in California: Seismological and tectonic aspects in Journal of Geophysical Research, v., 100, no. B7, p. 12235-12355.

    Jones, L.M., Bernknopf, R., Cox, D., Goltz, J., Hudnut, K., Mileti, D., Perry, S., Ponti, D., Porter, K., Reichle, M., Seligson, H., Shoaf, K., Teriman, J., and Wein, A., 2008. The Shakeout Scenario, USGS Open File Report 2008-1150, CGS Preliminary Report 25, Version 1.0.

    Larsen, T., Bolton, M.K., and David, K.M., 2015. Pinpointing the Cost of Natural Disasters – Local Devastation and Global Impact in proceedings SECED 2015 Conference: Earthquake Risk and Engineering towards a Resilient World 9-10 July 2015, Cambridge UK, 11 pp.

    Porter, K., Jones, L., Cox, D., Goltz, J., Hudnut, K., Mileti, D., Perry, S., Ponti, D., Reichle, M., Rose, A.Z. Scawthorn, C., Seligson, H.A., Shoaf, K.I., Treiman, J., and Wein, A., 2011. The ShakeOut Scenario: A Hypothetical Mw7.8 Earthquake on the Southern San Andreas Fault in Earthquake Spectra, v. 27, no. 2., p 239-261, DOI: 10.1193/1.3563624

    Swift, J., Wilson, J., and Le, T.N., 2012. Estimated Temporal Variation of Losses Due to a Recurrence of the 1933 Long Beach Earthquake in Earthquake Spectra, v. 28, no. 1, p. 347-365 DOI: 10.1193/1.3672995

    Read about the earthquake that killed insurance at the Jumpstart Blog here.

    Learn more about the tectonics behind the 17 January 1994 M=6.7 Northridge earthquake here.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States
    1

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

     
  • richardmitnick 10:57 am on January 8, 2019 Permalink | Reply
    Tags: , , , , In the late evening on January 3 a M=5.1 earthquake caused strong local ground shaking in Nagomi-machi, , Quake Connectivity, , temblor   

    From temblor: “Quake Connectivity: 3 January 2019 M=5.1 Japan shock was promoted by the April 2016 M=7.0 Kumamoto earthquake” 

    1

    From temblor

    January 7, 2019
    By Shinji Toda, Ph.D. (IRIDeS, Tohoku University)
    Ross S. Stein, Ph.D. (Temblor, Inc.)

    Was the small but strong shock in southern Japan a random event?

    In the late evening on January 3, a M=5.1 earthquake caused strong local ground shaking (JMA Intensity 6-, equivalent to MMI Intensity IX-X) in Nagomi-machi, ~25 km north of Kumamoto City (Fig. 1). Although the quake brought only light damage to the town, it stopped the Shinkansen ‘bullet trains’ and highway services for an emergency check-up during Japan’s well-traveled New Year holiday.

    1
    Figure 1. JMA intensity distribution of the January 3 M=5.1 earthquake. At the epicenter (X), the shaking reached JMA 6-.

    Japan’s Headquarters for Earthquake Research Promotion (HERP) declares the M=5.1 to be unrelated to the 2016 M=7.0 shock. We beg to differ.

    This quake recalls the devastating 2016 Mw=7.0 (Mjma=7.3) Kumamoto earthquake that killed 50 people and destroyed thousands of houses (Hashimoto et al., 2017). Immediately after the M=5.1 shock, HERP (2019) announced that there is no causal relation between the 3 Jan 2019 shock and the 15 April 2016 Kumamoto earthquake. In contrast, we contend that the M=5.1 is instead part of the long-lasting and remarkably widespread aftershock sequence of the M=7.0 Kumamoto earthquake.

    2
    Figure 2. (Left panel) Coulomb stress imparted by the 2016 Kumamoto earthquake sequence to the surrounding crust as a result of the combined Mw=6.0 and Mw=7.0 shocks. This figure was originally posted in a Temblor blog (Stein and Toda, 2016). Regions in which strike-slip faults are brought closer to failure are red (‘stress trigger zones’); regions now inhibited from failure are blue (‘stress shadows’). Aftershocks during first three months (translucent green dots) generally lie in regions brought closer to failure. The January 3 event (yellow star) is located in one of the stress trigger zones.

    (Right panel) Seismicity rate change between before (2009/01/01-2016/04/14) and after (2016/04/14-2019/01/02) the 2016 Kumamoto earthquake sequence. Red areas ‘turned on’ after the 2016 mainshock; blue areas ‘shut down.’

    The M=5.1 shock struck in a previously published Coulomb ‘stress trigger zone’

    In the web article of the IRIDeS Tohoku University released immediately after the 2016 shock (IRIDeS, 2016) and our blog article posted on September 2, 2016 (Stein and Toda, 2016), we emphasized the effect of Coulomb stress transfer to nearby regions (warmer color regions in Fig. 2 left panel), and mentioned the initial aftershocks mostly occurred in the regions where we calculated that the Coulomb stress increased. The Jan 3, 2019 M=5.1 shock indeed occurred in one of the stress increased lobes (yellow star in Fig. 2). This lobe experienced an increase in seismicity after the Kumamoto mainshock (Box A in Fig. 3 below).

    3
    Figure 3. Epicenters of all earthquakes shallower than 20 km during the period of 2015-2018 (JMA catalog). Although there are several dense clusters that have nothing to do with the Kumamoto earthquake, we nevertheless see that the aftershock zone is extends up to five rupture lengths from the fault (thick black line). The three boxes are where we examined the seismicity over time in Figure 4.

    The quake rate doubled in the stress trigger zone of the 2016 Mw=7.0 quake, and dropped by a factor of 5 in its stress shadow.

    Given that Japan is such an earthquake-prone country, one could argue that it was simply a random accident that the M=5.1 quake struck in the stress trigger zone. To address this possibility, we first examined the change in earthquake occurrence rate (‘seismicity rate change’) before and after the 2016 Kumamoto earthquake (Fig. 2 right panel). A visual comparison of our Coulomb calculation (Fig. 2 left panel) with seismicity rate change (Fig. 2 right panel) shows they match reasonably well. The epicenter of the 3 January 2019 event is in the red spot on both maps. Furthermore, regions north and south of the 2016 rupture zone, in which the faults were inhibited from failure by the stress changes, indeed show a seismicity decrease.

    To make sure that the local seismicity responded to the Kumamoto earthquake and not some other event at roughly the same time, we have chosen three sub-regions (boxes in Fig. 3) and looked at their seismicity time series (Fig. 4). In box A, the number of shocks, most of which are very small, was ~600 a year before the 2016 mainshock. But it has risen by over 2, to ~1500 per year since the mainshock. Thus, the M=5.1 event occurred in the zone of sustained higher rate of seismicity associated with the 2016 Kumamoto earthquake. A similar continuous and long-lasting seismicity increase also occurred in box C (northern Miyazaki Prefecture) where Coulomb stress was also imparted by the mainshock. The opposite response is observed in box B, where Coulomb stress was calculated to have decreased. There, the seismicity plummeted to 1/5 of the pre-Kumamoto level.

    4
    Figure 4. Seismic time series in the particular sub-regions, A, B, and C, corresponding to the boxes in Fig. 2 left panel and Fig. 3. The blue line indicates cumulative number of earthquakes since 2015 (with the corresponding blue scale at left), whereas the green stems identify each earthquake time and magnitude (green scale at right). What’s clear is that in all cases, the seismicity rates changed roughly at the time of the 2016 Kumamoto mainshock, and in the manner forecast by the Coulomb stress changes.

    There is a caveat that the Japan Meteorological Agency (JMA) has changed their earthquake determination algorithm after April 2016. However, it should have been homogeneously implemented in Kyushu. Since we confirmed the regional-dependent seismic behaviors in Fig. 4, we do not think the increased seismicity in the box A in Fig. 4 is an artifact. We also note that the rate of shallow M≥5 earthquakes under inland Japan (378,000 km2) is roughly about 10 a year. It enables us to say the probability to have one M≥5 quake in the box A (1168 km2) per year is ~3%, and so it is rare enough to make an accidental or coincidental occurrence unlikely.

    The long-lasting and far-reaching impact of stress transfer on seismic hazard.

    A key lesson learned from this M=5.1 quake is the effect of stress disturbance due to the three-year-old M=7 event continues over a large area in central Kyushu. And even though the size of the January 3 quake is much smaller than the M=7.0, it can nevertheless cause serious damage. Further, aftershocks do not get smaller with time after a mainshock; instead they only get more spaced out in time. So, a larger shock could still strike. The most likely place for such an event is unfortunately the highly-populated Kumamoto city, because there the stress imparted by the 2016 mainshock was greater than anywhere else.

    References

    Manabu Hashimoto, Martha Savage, Takuya Nishimura, Haruo Horikawa and Hiroyuki Tsutsumi (2017), Special issue “2016 Kumamoto earthquake sequence and its impact on earthquake science and hazard assessment” Earth, Planets and Space, 69-98, https://earth-planets-space.springeropen.com/articles/10.1186/s40623-017-0682-7

    Headquarters for Earthquake Research Promotion (2019), https://www.static.jishin.go.jp/resource/monthly/2019/20190103_kumamoto.pdf

    IRIDeS (International Research Institute of Disaster Science) (2016), http://irides.tohoku.ac.jp/event/2016kumamotoeq_science.html

    Ross S. Stein and Volkan Sevilgen (2016), The Tail that Wagged the Dog: M=7.0 Kumamoto, Japan shock promoted by M=6.1 quake that struck 28 hr beforehand http://temblor.net/earthquake-insights/japan-542/

    Ross S. Stein and Shinji Toda (2016), How a M=6 earthquake triggered a deadly M=7 in Japan, Temblor http://temblor.net/earthquake-insights/how-a-m6-earthquake-triggered-a-deadly-m7-in-japan-1304/

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States
    1

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

     
  • richardmitnick 10:08 am on December 24, 2018 Permalink | Reply
    Tags: , , , Sunda Strait tsunami launched by sudden collapse of Krakatau volcano into the sea, temblor   

    From temblor: “Sunda Strait tsunami launched by sudden collapse of Krakatau volcano into the sea” 

    1

    From temblor

    December 23, 2018
    Jason Patton

    Residents of the islands of Sumatra and Java were surprised by an unexpected tsunami yesterday. At the time we write this, there are reports of over 200 unfortunate deaths.

    Cause: Earthquake, Landslide, or Volcanic Eruption?

    1
    Satellite imagery comparison based on Copernicus Sentinel-1 satellite imagery.

    ESA/Sentinel 1

    Tsunami can be triggered by 4 processes: earthquakes, landslides, weather causes (storms), and volcanic eruptions. Tide gages in the Sunda Strait recorded the tsunami and there is a wide range of observations that can be found on social media. Tsunami caused by submarine landslides can be nearly impossible to plan for and there is typically very little advance notice.

    The Sunda Strait is the seaway that is formed between the islands of Java and Sumatra, Indonesia. This area of the world is best known for the 1883 eruption of Krakatau (or Krakatoa). This is a region of active tectonics and the deadly earthquake and tsunami from 2004 is still in our minds and hearts, not to mention the tsunami in Palu, Sulawesi, Indonesia just a short time ago.

    After the tsunami hit, people immediately thought about the Anak Krakatau volcano as a possible source, where there has been ongoing eruptions for several years. This volcano is located where the 1883 eruption happened and is part of the same volcanic system. There are ongoing efforts to monitor this volcanic system (Hoffmann-Rothe, et al., 2006).

    The vitally important service from national organizations like the European Union provide near real time satellite imagery. When compared with historic imagery, we have the ability to evaluate changes at the Earth’s surface.

    The landslide could have itself been triggered by earthquakes or an eruption. Considering the low level of seismicity, the eruption is the likely culprit. Because the eruption is continuing, the possibility for additional landslides and tsunami should be considered for people who live along the coastline in the Sunda Strait.

    We have outlined the general location of the shoreline on these images to take a first glance at the size of the landslide. The images are imperfect and this analysis is an approximation. The source of the satellite imagery is listed in the references below.

    We have also outlined the spatial extent of the shoreline of Krakatau prior to the 1883 eruption.

    Krakatau

    The eruption in 1883 is known around the world because it had a global impact upon the climate for several years. Simon Winchester wrote a book entitled Krakatoa: The Day the World Exploded, August 27, 1883 and this is considered an excellent text that helps people learn about the eruption and the impact of volcanic hazards.

    The 1883 eruption also caused a tsunami that caused devastation along the coastline and killed several thousand people. Below is a lithograph showing the 1883 eruption. This was published in 1888 (Royal Society, 1888).

    2
    An 1888 lithograph of the 1883 eruption of Krakatoa.

    The Smithsonian Institution has an excellent website that covers the monitoring of volcanoes around the globe. Here is the webpage for the Anak Krakatau volcano.

    There are lots of videos and photos of the ongoing eruptions. Below is a spectacular video taken from an airplane sent by the Indonesian Government to investigate the situation.

    These natural hazards span the globe. Learn more about your exposure to natural hazards at temblor.net.

    Tsunami Without Warning

    The tsunami lasted about an hour in places and created both sea level rise and fall.

    Below are two tide gage records from the region nearest the volcanic islands in the Sunda Strait. The upper panels show the tsunami records. The lower panel is a map showing the locations relative to Anak Krakatau.

    3

    4

    Tide gage records from http://tides.big.go.id . Vertical scale is in meters (about the same size as a yard).

    The tide gage record reveals that there was about 40 minutes from the first wave arrival to the highest and most destructive inundation. So, even without an expensive tsunami warning buoy system, or without a Krakatau Island seismic and GPS monitoring network, we can see, in retrospect, that warning was possible. A rate-of-change detector on tide gages could have been effective if a signal were sent to cell phones.

    Out of the 2004 ‘Boxing Day’ M=9.2 earthquake tsunami catastrophe was born the DART buoy system in the Pacific and Indian Oceans. Out of the 2011 M=9.0 Tohoku earthquake tsunami disaster was born much faster and more accurate tsunami warnings when triggered by large offshore quakes.

    Wouldn’t it be great if, out of this tragedy, a simple but effective warning system arose that could be ‘bolted on’ to existing telemetered tide gages that are already in place along the Pacific Ring of Fire and other volcanic centers?

    References:

    Hoffmann-Rothe, A., Seht, M.I-V., Knieb, R., Faber, E., Klinge, K., Reichert, C., Purbawinata, M.A., and Patria, C., 2006. Monitoring Anak Krakatau Volcano in Indonesia in EOS Transactions, v. 87, no. 81, p. 581, 585-586

    Royal Society, 1888. The Eruption of Krakatoa and Subsequent Phenomena, Report of the Krakatoa Committee of the Geological Society, London, Trubner and Co.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States
    1

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

     
  • richardmitnick 2:06 pm on November 17, 2018 Permalink | Reply
    Tags: Earthquakes and Potential for Levee Failure, Interview with Dr. Stewart, temblor, Water Management: Levees and Subsidence, When the Levee Breaks: Cascading failures in the Sacramento-San Joaquin River Delta California   

    From temblor: “When the Levee Breaks: Cascading failures in the Sacramento-San Joaquin River Delta, California” 

    1

    From temblor

    November 16, 2018
    Jason R. Patton, Ph.D., Ross Stein, Ph.D., Volkan Sevilgen, M.Sc.

    Water Management: Levees and Subsidence

    The state of California provides a substantial proportion of food for our country and other nations. Because of this agribusiness history in the state, water rights have been a durable [recurrent] topic in the politics of the state and the western US.

    Competing interests for the limited water resources have resulted in dramatic debate about the management of the Sacramento – San Joaquin River Delta. Islands and agricultural land in this region were protected by flooding by the installation of levees. Levees are artificial stream banks, designed to prevent flooding the islands and the land adjacent to the river. The islands are composed of peat, and once the levees prevented seasonal flooding, the peat began to outgas and compact. So, today the islands are over 15 ft below the river level, which is at sea level. In fact, the islands are like empty bowls with their rims just above the river level. If the levees are breached in even a modest earthquake, the river water would rush in to flood the islands.

    But the loss of the islands are just the tip of the iceberg. The real problem is that so much water would be displaced from the Sacramento River that sea water from San Pablo and Suisun Bays would be sucked in, rendering the Delta-Mendota Canal useless for irrigating the verdant crops of the Great Valley.

    The figure below shows the spatial extent of this land subsidence. The color represents the magnitude of this subsidence relative to feet below sea level (Windham-Meyers et al., 2018). The levees are currently the only physical barrier that prevents these regions from flooding with salty water.

    2
    Sacramento – San Joaquin Delta wetlands are shown with color representing the magnitude of subsidence below sea level (modified from Galloway et al., 1999). The red box represents the area that was studied by Windham-Meyers et al. (2018) for the potential for greenhouse gas emissions from peat in these wetlands.

    Earthquakes and Potential for Levee Failure

    The levees in the Delta are highly susceptible to failure due to earthquakes because they were built out of mud between the Gold Rush and the 1906 Earthquake. The 2014 South Napa earthquake is a reminder that even small quakes on faults with low slip rates can cause strong (0.5 g) shaking. The Delta is just east of some major faults, and straddles others.

    Below is a summary map showing the relative potential for levee collapse due to earthquakes in the Delta (Mount and Twiss, 2005). According to these authors, there is a 2 in 3 chance that either floods or an earthquake will cause catastrophic flooding in the Delta by 2050. These authors combined estimates of earthquake ground shaking and knowledge about the conditions of the levees in the Delta to prepare this map that shows relative damage potential for different zones.

    3
    Zones of potential damage from earthquake induced liquefaction and levee collapse (modified from Torres et al., 2000).

    Millions of people in the United States and elsewhere are exposed to flood hazards. When one is exposed to these flood hazards, they are at risk. Learn more about your exposure to flood hazards at the Temblor app here.

    Below is a map showing flood hazards and earthquake faults in the Delta area. Blue represents the chance of flooding in 10 years. Darker blue represents higher flood hazard. The flood hazard is based on the FEMA flood zones. The major USGS active faults shown in red are labeled.

    4
    Flood hazards shown using the Temblor app. Earthquake faults and recent earthquakes are also shown.

    Below is an animation that shows a visualization of what will likely happen if there are levee collapses in the Delta. First we see where the islands will be flooded following an earthquake. Then we see a simulation of the changes in salinity for the areas that are flooded (the islands). Animation provided courtesy of Metropolitan Water District of Southern California.


    Animation of earthquake induced failures of Delta levees which protect deeply subsided islands or “holes”. This large void below sea-level and sudden collapse can pull over one million acre-feet of sea water into the Delta significantly impacting the water supply for millions of Californians and millions of acres of farmland. Seismic risks from Delta Risk Management Strategy, California Department of Water Resources 2009.

    Interview with Dr. Stewart

    Jonathan Stewart, Ph.D. is a professor of geotechnical engineering, earthquake engineering, and engineering seismology and the Chair of the Department of Civil and Environmental Engineering at the University of California, Los Angeles. Dr. Stewart has been studying the interactions between structures (like the levees) and earthquakes for over 2 decades.

    Temblor asked Dr. Stewart some questions about a recent talk they gave to scientists and engineers.

    Temblor: This subject matter is complicated from a political perspective, a geotechnical perspective, and a natural hazards perspective. Some of the natural hazards in the Delta have been exasperated by our management of the natural resources there. What do you view is the most important message that the scientific facts tell us about the enhanced risk of flooding in the Delta due to our management of the natural resources in this area?

    Dr. Stewart: The Delta region is indeed complex, but the seismic risk is easy to understand. The levees, when viewed as individual earth structures, are highly vulnerable to the effects of earthquakes. Many factors contribute to this, including the lack of engineering in their original construction in many cases, subsidence of the interior islands, which effectively heightens the levees, and the extraordinarily soft peaty organic soils upon which they are founded. Furthermore, the levees constantly impound water, meaning that portions of the levee fill are constantly saturated and susceptible to liquefaction. If a significant earthquake occurs on the active faults near the west end of the Delta, we expect multiple breaches. It is also important to recognize that failure of any one levee segment would inundate the interior island, and thus would represent a failure of the levee system.

    Because of the way we have managed the Delta, when these breaches occur, saline water from San Francisco Bay will be drawn into the Delta as the below sea level islands fill. This will be a disaster for the water distribution system in California and the regional ecology.

    Temblor: There exist a wide range of contributing factors for flood hazards in the Delta. Some factors are beyond our control. Please tell us about the most important factors that are beyond our control.

    Dr. Stewart: The occurrence of earthquakes on the regional faults, is of course, beyond our control. Levee stability is also affected by sea level rise, and high water events related to extreme upstream precipitation. Such events are under our control to some extent in that they are influenced by climate change, but the ‘our’ becomes very large as this is a national and global problem.

    Temblor: California has just elected Gavin Newsom as Governor, who has demonstrated an awareness for earthquake hazards in the past when he served as the Mayor of San Francisco and as the Lieutenant Governor for the state of California. So, is this the moment to seize the day and get the federal and state governments to act now to prevent this predictable disaster from occurring? What should they do?

    Dr. Stewart: Absolutely. If we suffer a catastrophic failure of our water distribution system due to an earthquake in the Delta before we act, history will not judge our political and engineering leaders kindly. The threat is real, and the science refutes those who would deny it. We must act. We know how to address this problem through solutions like the California Water Fix program, we just need the political will to see it through in a timely way.

    Learn More

    Learn more about this history of the Delta from this report prepared for the San Francisco Estuary Institute and Aquatic Science Center (Whipple et al., 2012). The report is available in pdf format and the GIS data are also posted online.

    Dr. Stewart and their colleagues prepared a report about the factors and processes that contribute to the stability of levees in the Delta (Deverel et al., 2016). Read this report here.

    References

    Deverel, S.J., Bachand, S., Brandenberg, S.J., Jones, C.E., Stewart, J.P., and Zimmaro, P., 2016. Factors and Processes Affecting Delta Levee System Vulnerability in San Francisco Estuary and Watershed Science, v. 14, no. 4. https://doi.org/10.15447/sfews.2016v14iss4art3

    Galloway, D.L., Jones, D.R., and Ingebritsen, S.E., 1999. Land subsidence in the United States. USGS Circular 1182, https://pubs.usgs.gov/circ/circ1182/#pdf

    Shouse, M.K., and Cox, D.A., 2013. USGS Science at Work in the San Francisco Bay and Sacramento-San Joaquin Delta Estuary: U.S. Geological Survey Fact Sheet 2013–3037, 6 p., https://pubs.usgs.gov/fs/2013/3037/

    Torres RA, et al. 2000. Seismic vulnerability of the Sacramento-San Joaquin Delta levees. Report of levees and channels technical team, seismic vulnerability sub-team to CALFED Bay-Delta Program. 30 p.

    Whipple, A., Grossinger, R. M., Rankin, D., Stanford, B., Askevold, R.A., 2012. Sacramento-San Joaquin Delta Historical Ecology Investigation: Exploring Pattern and Process. SFEI Contribution No. 672. SFEI: Richmond

    Windham-Meyers, L., Bergamaschi, B., Anderson, F., Knox, S., Miller, R., and Fujii, R., 2018. Potential for negative emissions of greenhouse gases (CO2, CH4 and N2O) through coastal peatland re-establishment: Novel insights from high frequency flux data at meter and kilometer scales in Env. Res. Letters, v. 13., https://doi.org/10.1088/1748-9326/aaae74

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States
    1

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

     
  • richardmitnick 11:39 am on October 27, 2018 Permalink | Reply
    Tags: , , , , , , , temblor, The Whistle   

    From temblor: “The Whistle: Are We Ready for the Big One?” 

    1

    From temblor

    October 24, 2018

    Jason R. Patton, Ph.D.
    Ross Stein, Ph.D.
    Volkan Sevilgen, M.Sc.

    It Has Happened Before

    The southern San Andreas fault (SSAF) is a plate boundary strike-slip fault, where the Pacific plate moves northward relative to the North America plate. There have been large earthquakes on this fault in historic time, including the 1857 Forth Tejon earthquake. This 1857 earthquake is estimated to have been a magnitude 7.9 earthquake (larger than the recent earthquake in Sulawesi, Indonesia). There is also a record of prehistoric earthquakes on this fault, spanning the past 5000 years (Weldon et al., 2004; Sharer et al., 2007). These authors have determined that the average time between earthquakes on the SSAF is 105 years. However, the time between earthquakes ranges from 31 – 165 years. This large variation in inter-event time periods makes it more difficult to know when the next “Big One” will happen.

    The USGS prepares earthquake scenarios based on our knowledge about past earthquakes and how future earthquakes may behave based on our empirical knowledge. Below is a USGS scenario map for the part of the SSAF that ruptured in the 1857 Fort Tejon earthquake. The color scale represent relative earthquake shaking intensity based on the Modified Mercalli Intensity scale. Warmer colors represent areas of stronger ground shaking. While the map below is based on a computer model, this is a good estimate of how strongly the ground shook in 1957. Note how the strongest ground shaking is adjacent to the fault.

    1
    USGS Shakemap scenario map for the southern San Andreas fault, showing an estimate of shaking intensity from an earthquake similar in length and magnitude to the 1857 Fort Tejon earthquake. The part of the fault that slips in this scenario earthquake is shown as a black line, very similar to the known extent of the 1857 earthquake.

    Several governments and non-governmental organizations prepare estimates of seismic hazard so that people can ensure their building codes are designed to mitigate these hazards. The Global Earthquake Model (GEM) is an example of our efforts to estimate seismic hazards on a global scale. Temblor.net uses the Global Earth Activity Rate (GEAR) model to provide estimates of seismic hazard at a global to local scale (Bird et al., 2015). GEAR blends quakes during the past 41 years with strain of the Earth’s crust as measured using Global Positioning System (GPS) observations.

    Below is a map prepared using the temblor.net app. Seismicity from the past month, week, and day are shown as colored circles. The temblor app suggests that this region of San Bernardino, CA has an earthquake score of 93. To find out what your earthquake score is, enter your address in the app at temblor.net.

    2
    Earthquake Risk map for southern California, centered on the inland empire. Active faults are shown as red lines. Earthquakes from the past month are shown as circles.

    We Imagine the Consequences

    Earthquakes can cause damage to buildings and other infrastructure due to the shaking intensity. The closer to the earthquake, the higher the intensity. Buildings are located on different types of bedrock and this can amplify the shaking intensity in places. How do we know this? We have made direct observations of the damage from earthquakes.

    There is ample evidence of what happens during earthquakes like what will occur on the SSAF someday. The same fault system, further north, has also ruptured in historic time. In 1868, the Hayward fault (a sister fault of the San Andreas) had an earthquake that caused extensive damage in the San Francisco Bay area. The USGS and the California Geological Survey are using the 150 year anniversary of this earthquake as a tool to educate the public about earthquake hazards along these active faults in northern California. Here is a short video about the HayWired Scenario. More can be learned about how to outsmart disaster at the “HayWired” website here.

    Below is a photo from the aftermath of the 1868 Hayward fault earthquake.

    3
    This photo shows damage to “Pierce’s House,” a building damaged by the 1868 Hayward fault earthquake. Image source: Wikimedia Commons, public domain.

    Another historic earthquake that caused extensive damage in California is the 1906 Great San Francisco earthquake, another San Andreas fault earthquake. The damage from this earthquake included building damage and fire. Fire is one of the most common damaging effects of an earthquake like what will happen someday on the SSAF.

    Below is a photo showing damage to houses that were built on material that did not perform well during an earthquake.

    4
    Photo of houses following the 1906 San Francisco earthquake. Photo from National Archives Record Group 46, public domain.

    The combination of hazard and exposure (people) is what we call risk. When people are exposed to earthquake hazards, they are at risk from damage due to those earthquakes. If there is an earthquake and nobody is there to experience the earthquake, there is no risk. One major difference between 1868, 1906, and today is that there are more people that live close to these earthquake faults. While the average number of earthquakes stays relatively constant through time, as the population grows in earthquake country, the risk also grows.

    Do you live along the San Andreas or some other plate boundary fault? What about another kind of fault?

    To learn more about your exposure to these hazards, visit temblor.net.

    When is the next Big One?

    We don’t know when the next southern San Andreas fault big earthquake will happen. Currently there are no scientifically demonstrated ways to predict earthquakes. We can use the frequency of past earthquakes and patterns of earthquake occurrence (current seismicity) to estimate the chance that an earthquake will occur over a period of time.

    These estimates of future earthquake occurrence are called forecasts. Most people are familiar with weather forecasts, but we know much less about earthquakes than we do about weather. Because of this, earthquake forecasts may not have the same amount of accuracy that weather forecasts do. However, these forecasts are based on the latest cutting edge science about earthquakes and are monumentally better than simply tossing a coin. The cool thing about these forecasts is that the science behind them improves over time as we learn more about how earthquakes happen. This is another improvement over coin tosses, which flip pretty much the same as they did since coins were invented.

    The Whistle is an upcoming series of broadcasts produced by the Empire Network, a collaboration between KVCR, PBS, and National Public Radio.

    This four-part documentary series that dives into earthquake science, history, local and international earthquakes and tsunamis, California preparedness and immediate response, prevention, mitigation, retrofits, resilience, sustainability, conservation, incentives, challenges, new technologies… and solutions. Are we ready for the Big One?

    The first episode airs on October 25 and we will learn about earthquakes and the San Andreas fault:

    ______________________________________________________
    Earthquakes and the San Andreas fault. The Ring of Fire. What do we know about earthquakes today? What causes them, how often, why we know the Big One is due. Evolution of seismology and our understanding of earthquakes and plate tectonics. How did the First Nations and early European settlers deal with Earthquakes before modern technology? How dangerous is the threat and how much of an impact can a big earthquake cause? What will happen when the next big one hits?
    ______________________________________________________

    Episode 2 covers how our immediate response might unfold during and following the Big One. Episode 3 reviews our knowledge of the current state of infrastructures (buildings, roads) and how an earthquake might impact these investments in society. Finally, the 4th episode presents an evaluation of how we have improved our ability to be resilient in the face of disasters from the Big One following decades of applying the scientific method to our observations of earthquakes. How will Earthquake Early Warning work and how will we benefit from this? Learn more by watching The Whistle.

    The premiere for “The Whistle, Are We Ready for the Big One?” premieres on Thursday Oct. 25. Watch the first episode on television, or head to this website where the video will be available to stream online.

    3

    References

    Bird, P., Jackson, D. D., Kagan, Y. Y., Kreemer, C., and Stein, R. S., 2015. GEAR1: A global earthquake activity rate model constructed from geodetic strain rates and smoothed seismicity, Bull. Seismol. Soc. Am., v. 105, no. 5, p. 2538–2554, DOI: 10.1785/0120150058

    Sharer, K.M., Weldon, R.J.III., Fumal, T.E., and Biasi, G., 2007. Paleoearthquakes on the Southern San Andreas Fault, Wrightwood, California, 3000 to 1500 B.C.: A New Method for Evaluating Paleoseismic Evidence and Earthquake Horizons in Bull. Seismol. Soc. Am., v. 97, no. 4, p. 1054–1093, DOI: 10.1785/0120060137

    Weldon, R., Sharer, K.M., Fumal, T., and Biasi, G., 2004. Wrightwood and the Earthquake Cycle: What a Long Recurrence Record Tells Us About How Faults Work in GSA Today, v. 14, no. 9, doi: 10.1130/1052-5173(2004)0142.0.CO;2

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States
    1

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

     
  • richardmitnick 11:13 am on October 27, 2018 Permalink | Reply
    Tags: , , , , , Greek earthquake in a region of high seismic hazard, , , temblor   

    From temblor: “Greek earthquake in a region of high seismic hazard” 

    1

    From temblor

    October 26, 2018
    Jason R. Patton, Ph.D.
    Ross Stein, Ph.D.
    Volkan Sevilgen, M.Sc.

    An earthquake with a magnitude of M = 6.8 earthquake struck today along the coast of Greece, preceded by a M = 5.0 earthquake. This large earthquake was felt widely across the region, including Italy, Albania, Bulgaria, and Macedonia. . Greece is at the intersection of several different tectonic regimes and is spanned by a zone of increased seismic hazard evidenced by the GEAR seismic hazard model. The earthquake is related to the convergent plate boundary that spans the southern boundary of Greece. The Gulf of Corinth, where the strongest shaking was felt, is the most seismically active site in Greece.

    Tectonic Setting

    Greece is in the middle of a tectonic die, with the right-lateral strike-slip North Anatolia fault striking from the east and the Ionian trench subduction zone converging from the south. In addition, there is a rapid (10-15 mm per year) extension at the Corinth Rift, forming the Gulf of Corinth just northeast of today’s earthquake sequence.

    The interaction of these different plate boundaries results in overlapping fault systems of different types of faults. The southern boundary of Greece is characterized by the formation of thrust faults formed from compression due to the subduction of the Africa plate beneath the Anatolia plate.

    The North Anatolia fault is a high slip rate fault (it moves fast) and can generate large damaging earthquakes such as the 1999 M = 7.6 Izmit earthquake. Much of the North Anatolia fault has ruptured in the 20th century and many consider the segment of the fault that runs near Istanbul, Turkey, is thought to be ready to slip next.

    The map below shows how the North Anatolia fault enters the region and how the subduction zones may be offset by the Kefallonia fault (Kokkalas, et al., 2006). The Ionian trench is labeled “Hellenic Arc” in this map. The M = 6.8 earthquake is in the general location of the blue star.

    1
    Plate boundary faults are shown with symbols representing the type of plate boundary. Subduction zones are shown with triangles pointing in the direction of motion of the down-going plate. Strike-slip relative motion is shown as oppositely directed arrows. Thick black arrows show relative plate motion in mm per year. Thin arrows with black dots at their base are Global Positioning System plate velocities (reference vector scale is in lower right corner).

    Seismic Hazards

    Hundreds of millions of people globally live in earthquake country. Do you live along a subduction zone or other plate boundary fault? What about another kind of fault?

    To learn more about your exposure to these hazards, visit temblor.net.

    Several governments and non-governmental organizations prepare estimates of seismic hazard so that people can ensure their building codes are designed to mitigate these hazards. The Global Earthquake Model (GEM) is an example of our efforts to estimate seismic hazards on a global scale. Temblor.net uses the Global Earth Activity Rate (GEAR) model to provide estimates of seismic hazard at a global to local scale (Bird et al., 2015). GEAR blends quakes during the past 41 years with strain of the Earth’s crust as measured using Global Positioning System (GPS) observations.

    Below is a map prepared using the temblor.net app. Seismicity from the past month, week, and day are shown as colored circles. The rainbow color scale represents the chance of a given earthquake magnitude, for a given location, within the lifetime of a person (technically, it is the magnitude with a 1% chance per year of occurring within 100 km). The temblor app suggests that this region could have an earthquake with a magnitude of M = 7.0 to 7.25 in a typical lifetime, and so the M = 6.8 was by no means rare or unexpected.

    Note how the seismic hazard is increased along the North Anatolia fault in Turkey and follows this fault as it enters Greece. There is also an increased risk of earthquakes associated with the Ionian trench. This belt of increased seismic hazard is well correlated with the tectonic boundaries. Much of Greece lies within this zone of increased seismic hazard.

    3
    Global Earthquake Activity Rate map for this region of the western equatorial Pacific. Faults are shown as red lines. Warmer colors represent regions that are more likely to experience a larger earthquake than the regions with cooler colors. Seismicity from the past is shown and the location of the M 6.8 earthquake is located near the blue teardrop symbol.

    References

    Bird, P., Jackson, D. D., Kagan, Y. Y., Kreemer, C., and Stein, R. S., 2015. GEAR1: A global earthquake activity rate model constructed from geodetic strain rates and smoothed seismicity, Bull. Seismol. Soc. Am., v. 105, no. 5, p. 2538–2554, DOI: 10.1785/0120150058

    Kokkalas, S., Xypolias, P., Koukouvelas, I., and Doutsos, T., 2006, Postcollisional contractional and extensional deformation in the Aegean region, in Dilek, Y., and Pavlides, S., eds., Postcollisional tectonics and magmatism in the Mediterranean region and Asia: Geological Society of America Special Paper 409, p. 97–123

    More can be found about the seismotectonics of this region here.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States
    1

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

     
  • richardmitnick 2:46 pm on October 11, 2018 Permalink | Reply
    Tags: An earthquake with a magnitude of M = 7.0 earthquake struck today in New Britain, , , , Papua New Guinea, , , Subduction megathrust earthquake preceded by a foreshock, temblor   

    From temblor: “Subduction megathrust earthquake preceded by a foreshock” 

    1

    From temblor

    October 10, 2018
    Jason Patton

    An earthquake with a magnitude of M = 7.0 earthquake struck today in New Britain, Papua New Guinea. New Britain is an island northeast of the Island of Papua New Guinea and Australia. While the earthquake struck on a subduction zone, the Pacific Tsunami Warning Center states that there is no tsunami threat.

    Tectonic Hazards

    Hundreds of millions of people globally live along plate margins called subduction zones. These plate boundaries are formed as the result of millions of years of plate convergence. Earthquakes that occur along subduction zone megathrust faults are compressional earthquakes (aka thrust or reverse).

    Earthquake size is related to the material properties of the earth surrounding the slipped fault, the size of the fault that slipped (the area), and the amount that the fault slipped (distance). Earthquakes occur in specific depth ranges depending upon the conditions. Typical plate boundary earthquakes due to brittle failure along a fault extend to several tens of kilometers into the Earth. Because subduction zone megathrust faults dip into the earth at an angle, the fault area that can slip can be larger than for strike-slip faults. Megathrust earthquakes can therefore have magnitudes larger than strike-slip (shear) earthquakes.

    Do you live along a subduction zone or other plate boundary fault? What about another kind of fault?

    To learn more about your exposure to these hazards, visit http://www.temblor.net.

    Several governments and non-governmental organizations prepare estimates of seismic hazard so that people can ensure their building codes are designed to mitigate these hazards. The Global Earthquake Model (GEM) is an example of our efforts to estimate seismic hazards on a global scale. Temblor.net uses the Global Earth Activity Rate (GEAR) model to provide estimates of seismic hazard at a global to local scale (Bird et al., 2015). GEAR blends quakes during the past 41 years with strain of the Earth’s crust as measured using Global Positioning System (GPS) observations.

    Below is a map prepared using the temblor.net app. Seismicity from the past month, week, and day are shown as colored circles. The rainbow color scale represents the chance of a given earthquake magnitude, for a given location, within the lifetime of a person (technically, it is the magnitude with a 1% chance per year of occurring within 100 km). The temblor app suggests that this region could have an earthquake of M=7.9 in a typical lifetime, and so the M=7.0 was by no means rare or unexpected.

    There was a magnitude M = 5.9 earthquake just 12 minutes before the M 7.0 earthquake, and so, in retrospect, we might consider the M = 5.9 a ‘foreshock’ to the much larger M = 7.0 earthquake. This happens only about 5-10% of the time, which means that foreshocks are a poor predictor of mainshocks.

    1
    Global Earthquake Activity Rate map for this region of the western equatorial Pacific. Faults are shown as red lines and the megathrust faults are shown as pink regions because they dip into the earth at an angle. Warmer colors represent regions that are more likely to experience a larger earthquake than the regions with cooler colors. Seismicity from the past is shown and the location of the M 7.0 earthquake is located near the blue teardrop symbol.

    New Britain Tectonics

    This area of the world is one of the most active and tortured plate boundaries in the world. There are several subduction zones, oceanic spreading ridges, and transform plate boundary faults that interact to form the island of New Britain, Bougainville Island, and the ocean basins below the Solomon and Bismarck seas.

    New Britain is part of a magmatic arc (volcanic island) related to the subduction of the Solomon Sea plate beneath the Bismarck Sea plate. Below is a map showing the major plate boundary faults in this region. The Island of New Britain is located in the southern part of the South Bismarck plate.

    2
    Plate tectonic map from Oregon State University. The Solomon Sea plate subducts beneath the South Bismarck plate to the north, the Pacific plate to the east, and the Australia plate to the south. There are oceanic spreading ridges shown as double black lines. Some of these ridges are offset by transform (strike-slip) faults between the South and North Bismarck Sea plates.

    Earlier this year, there was an earthquake about 20 miles from today’s earthquake. Dr. Stephen Hicks is a postdoctoral research fellow in seismology from the University of Southampton who has been studying the geometry of the subduction zone in associated with the New Britain Trench. Here is his tweet regarding the M = 6.6 earthquake in March 2018. This was a foreshock to an M = 6.9 earthquake a few days later.

    Below are the two panels that show earthquake epicenters on the left and earthquake in cross-section on the right. The location for the M = 6.6 is shown as an orange star on the cross section and a yellow star on the map. We have added the location of the M = 6.9 earthquake using the same color scheme. We also added the location for the M = 7.0 earthquake from today as a blue star.

    4
    Seismicity map and cross section (modified from Dr. Hicks, 2018). Epicenters are shown on the map, with the earthquakes selected for the cross section is outlined as a dashed rectangle labelled A-A’. Hypocenters along cross section A-A’ are shown relative to distance from the trench axis.

    Take Away

    A subduction zone megathrust earthquake with a magnitude M = 7.0 happened along one of the most seismically active subduction zones, the New Britain Trench. The magnitude and depth are the probable reasons that the Pacific Tsunami Warning Center announced that there is no tsunami threat from this earthquake, locally or globally. There was a M = 5.9 foreshock several minutes prior to the mainshock. This subduction zone has a potential for a larger earthquake.

    References

    Bird, P., Jackson, D. D., Kagan, Y. Y., Kreemer, C., and Stein, R. S., 2015. GEAR1: A global earthquake activity rate model constructed from geodetic strain rates and smoothed seismicity, Bull. Seismol. Soc. Am., v. 105, no. 5, p. 2538–2554, DOI: 10.1785/0120150058

    Hamilton, W., 1979, Tectonics of the Indonesian region: U.S. Geological Survey Prof. Paper 1078.

    Holm, R. and Richards, S.W., 2013. A re-evaluation of arc-continent collision and along-arc variation in the Bismarck Sea region, Papua New Guinea in Australian Journal of Earth Sciences, v. 60, p. 605-619.

    Lin, J., and R. S. Stein (2004), Stress triggering in thrust and subduction earthquakes and stress interaction between the southern San Andreas and nearby thrust and strike-slip faults, J. Geophys. Res., 109, B02303, doi:10.1029/2003JB002607

    More can be found about the seismotectonics of this region here.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States
    1

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

     
  • richardmitnick 7:32 am on September 21, 2018 Permalink | Reply
    Tags: A tectonic squeeze may be loading three thrust faults beneath central Los Angeles, , , , , temblor   

    From temblor: “A tectonic squeeze may be loading three thrust faults beneath central Los Angeles” 

    1

    From temblor

    September 17, 2018
    Chris Rollins

    Thrust-faulting earthquakes are a fact of life in Los Angeles and a threat to it. Three such earthquakes in the second half of the 20th century painfully etched this ongoing threat to life, limb and infrastructure into the memories and the backs of the minds of many who call this growing metropolis home. The first struck 40 seconds after 6:00 AM on a February morning in 1971 when a section of a thrust fault beneath the western San Gabriel Mountains ruptured in a magnitude 6.7 tremor. The earthquake killed 60 people, including 49 in the catastrophic collapse of the Veterans Administration Hospital in Sylmar, the closest town to the event (which is often referred to as the Sylmar earthquake). Among other structures hit hard were the newly built Newhall Pass interchange at the junction of Interstate 5 and California State Route 14, of which multiple sections collapsed, and the Van Norman Dam, which narrowly avoided failure in what could have been a cruel deja vu for a city that had been through deadly dam disasters in 1928 and 1963.

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    Devastation at the Veterans Administration Hospital in the 1971 Sylmar earthquake. Photo courtesy of Los Angeles Times.

    Sixteen years later, a section of the Puente Hills thrust fault ruptured in the magnitude 5.9 Whittier Narrows earthquake, killing eight people in East Los Angeles and bringing attention to a class of thrust faults that do not break the surface, called “blind” thrust faults, which will go on to form a key part of this story. Then early on another winter morning in 1994, an even more deeply buried blind thrust fault ruptured beneath the San Fernando Valley in the magnitude 6.7 Northridge earthquake, causing tens of billions of dollars in damage and taking 57 lives. One of the fatalities was Los Angeles police officer Clarence Wayne Dean, who died on his motorcycle when a span of the Newhall Pass interchange that had been rebuilt following the 1971 Sylmar earthquake collapsed again as he was riding across it in the predawn darkness.

    2
    Collapse of the Newhall Pass (I-5/CA-14) interchange in the 1994 Northridge earthquake. Officer Dean died on the downed section of overpass at right. The interchange has since been renamed the Clarence Wayne Dean Memorial Interchange in his memory. Photo courtesy of CNN.

    LA’s problem: The squeeze

    Thrust earthquakes like these, in which the top side of the fault is thrust up and over the bottom side, will likely strike Los Angeles again in the 21st century. They may in fact pose a greater hazard to the city than earthquakes on the nearby San Andreas Fault because they can occur directly beneath the central metropolitan area. This means that a city that has found so much of its identity and place in history from being improvised as it went, and from being a cultural and economic melting pot, now faces the unwieldy task of readying its diverse infrastructure and populace for the strong shaking these kinds of earthquakes can produce.

    One way that the earthquake science community has been assessing the seismic hazard in LA is by using geodesy – long-term, high-precision monitoring of the deformation of the Earth’s surface – to locate sections of faults that are stuck, or locked, causing the Earth’s crust to deform around them. It is this bending of the crust, or accumulated strain, that is violently released in earthquakes; therefore the locations where this bending is taking place might indicate where future earthquakes will occur, and perhaps how large and frequent they could be. Several decades of geodetic monitoring have shown that the greater Los Angeles area is being squeezed from north to south at roughly 8-9 millimeters per year (⅓ inch per year), about one-fourth the rate at which human fingernails grow. Thrust faults, such as those on which the Sylmar, Whittier Narrows and Northridge earthquakes struck, are ultimately driven by this compression.

    3
    Geodetic data, tectonics and material properties relevant to the problem. Dark blue arrows show the north-south tectonic compression inferred by Argus et al. [2005] after removing deformation caused by aquifer and oil use. Black lines are faults, dashed where blind. Background shading is a measure of material stiffness at the surface based on the Community Velocity Model [Shaw et al., 2015]. “Beach balls” show the locations and senses of slip of the 1971 Sylmar, 1987 Whittier Narrows and 1994 Northridge earthquakes. Figure simplified from Rollins et al. [2018].

    Why the science is still very much ongoing

    The task of linking the north-south tectonic squeeze to specific faults encounters several unique challenges in Los Angeles. First, the city sits atop not only active faults but also several aquifers and oil fields that have long provided part of its livelihood and continue to be used today, which deforms the crust around them. Geodetic data are affected by this anthropogenic deformation, to the extent that a recent study used these data to observe Los Angeles “breathing” water from year to year and even to resolve key hydrological properties of particular sections of aquifers. This spectacular deformation, which furnishes science that can be used in resource management around the world, has the unfortunate effect of obscuring the more gradual north-south tectonic shortening in Los Angeles in these data.

    4
    Animation from Riel et al. [2018] showing long-term subsidence of the Earth’s surface due to use of the Los Angeles and Santa Ana aquifers.

    Second, the faults are a complex jumble. The crust underlying Los Angeles is cut by thrust faults, strike-slip faults like the San Andreas Fault and subparallel to it, and other strike-slip faults nearly perpendicular to it. Although these faults all take part in accommodating the gradual north-south squeeze, the relative contributions of the thrust and strike-slip faults in doing so has been the subject of debate. The problem of estimating strain accumulation on subsurface faults is also generally at the mercy of uncertainties as to how faults behave at depth in the Earth’s crust and how they intersect and link up.

    Third, Los Angeles sits atop a deep sedimentary basin, created when a previous episode of extension created a “hole” in the crust that was gradually filled by sediments eroded off the surrounding mountain ranges. These sedimentary layers are more easily deformed than the stiffer rocks in the mountains around the basin, complicating the problem of estimating strain accumulation at depth from the way the surface is deforming. Finally, as in the case of the Puente Hills Fault, some of the major thrust faults in Los Angeles do not break the surface but are “blind.” This means that the bending of the crust around locked sections of these faults is buried and more difficult to detect at the surface.

    5
    Basin sediments affect the relationship between fault slip and deformation at the surface by up to 50% for the cases of the Puente Hills Fault (left) and Compton Fault (right). For the same fault slip, the basin is more compliant and so the Earth’s surface is displaced more (red arrows) than if it were absent (blue arrows). Figure simplified from Rollins et al. [2018].

    Three thrust faults may be doing a lot of the work

    Several important advances over the past two decades have paved pathways towards overcoming these challenges. The signal of deformation due to water and oil management can be subtracted from the geodetic data to yield a clearer picture of the tectonic shortening. The geometries of faults at depth have also come into focus, as earth scientists at the Southern California Earthquake Center and Harvard University have compiled decades of oil well logs and seismic reflection data to build the Community Fault Model, a detailed 3D picture of these complex geometries. A parallel effort has yielded the Community Velocity Model, a 3D model of the structure and composition of the Southern California crust that is internally consistent with the fault geometries.

    6
    A cross section of faults and earthquakes across central Los Angeles from Rollins et al. [2018]. Red lines are faults, dashed where uncertain; pairs of arrows along the thrust faults show their long-term sense of slip. White circles are earthquakes. Basin structure is from the Community Velocity Model.

    Recently, a team of researchers from Caltech, JPL and USC (with contributions from many other earthquake scientists) has begun to put these pieces together. Their approaches and findings were published in the Journal of Geophysical Research (JGR) this summer. On the challenge presented by the complex array of faults, the study found that the strike-slip faults probably accommodate less than 20% of the total shortening at the max, leaving the rest to be explained by thrust faulting or other processes. Three thrust faults, the Sierra Madre, Puente Hills and Compton faults, stand out in particular as good candidates. All three appear to span the Los Angeles basin from west to east, and the Puente Hills and Sierra Madre faults have generated moderate earthquakes in the last three decades, including the Whittier Narrows shock and a magnitude 5.8 tremor in 1991. Paleoseismology (the study of prehistoric earthquakes) has also revealed that these three faults have each generated multiple earthquakes in the past 15,000 years whose magnitudes may have exceeded 7.0.

    7
    Alternative models of how quickly strain is accumulating on the Compton, Puente Hills and Sierra Madre Faults, assuming that the transition between completely locked (stuck) and freely slipping patches of fault is gradual (left) or sharp (right), simplified from Rollins et al. [2018]. Gray lines are major highways.

    How fast is stress building up on these faults?

    Exploring a wide range of assumptions (such as whether the transitions between stuck and unstuck sections of faults may be gradual or abrupt), the team inferred that the Sierra Madre, Puente Hills and Compton faults appear to be partially or fully locked and building up stress on their upper (shallowest) sections. The estimated total rate of strain accumulation on the three faults is equivalent to a magnitude 6.7-6.8 earthquake like the Sylmar earthquake once every 100 years, or a magnitude 7.0 shock every 250 years. These back-of-the-envelope calculations, however, belie the fact that this strain is likely released by earthquakes across a wide range of magnitudes. The team is currently working to assess just how wide this range of magnitudes practically needs to be: whether the strain can be released as fast as it is accruing without needing to invoke earthquakes larger than Sylmar and Northridge, for example, or whether the M>7 thrust earthquakes inferred from paleoseismology are indeed a likely part of the picture over the long term.

    This picture of strain accumulation will sharpen as the methods used to build it are improved, as community models of faults and structure continue to be refined, and especially as more high-resolution data, such as that used to observe LA “breathing” water, is brought to bear on the estimation problem. The tolls of the Sylmar, Whittier Narrows and Northridge earthquakes in lives and livelihoods are a reminder that we should work as fast as possible to understand the menace that lies beneath the City of Angels.

    References

    Argus, D. F., Heflin, M. B., Peltzer, G., Crampé, F., & Webb, F. H. (2005). Interseismic strain accumulation and anthropogenic motion in metropolitan Los Angeles. Journal of Geophysical Research: Solid Earth 110(B4).

    Riel, B. V., Simons, M., Ponti, D., Agram, P., & Jolivet, R. (2018). Quantifying ground deformation in the Los Angeles and Santa Ana coastal basins due to groundwater withdrawal. Water Resources Research 54(5), 3557-3582.

    Rollins, C., Avouac, J.-P., Landry, W., Argus, D. F., & Barbot, S. D. (2018). Interseismic strain accumulation on faults beneath Los Angeles, California. Journal of Geophysical Research: Solid Earth 123, doi: 10.1029/2017JB015387.

    Shaw, J. H., Plesch, A., Tape, C., Suess, M. P., Jordan, T. H., Ely, G., Hauksson, E., Tromp, J., Tanimoto, T., & Graves, R. (2015). Unified structural representation of the southern California crust and upper mantle. Earth and Planetary Science Letters 415: 1-15.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States
    1

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

     
  • richardmitnick 2:43 pm on September 7, 2018 Permalink | Reply
    Tags: , , , , , , temblor, The ongoing earthquake sequence on the island of Hokkaido Japan   

    From temblor: “The ongoing earthquake sequence on the island of Hokkaido, Japan” 

    1

    From temblor

    September 6, 2018
    Jason Patton
    Jason R. Patton, Ph.D., Ross Stein, Ph.D., Shinji Toda, Ph.D, Volkan Sevilgen, M.Sc.

    The Nation of Japan is one of the most seismically active regions in the world and the people of Japan devote significant efforts to be resilient in the face of these hazards associated with earthquakes. These hazards include ground shaking, tsunami, landslides, and liquefaction. The historical knowledge of these hazards extends centuries into the past. Because of their efforts to learn using scientific methods, the world has learned more about earthquake processes.

    Everyone can benefit from learning about their exposure to natural hazards from earthquakes. To learn more about your exposure to these hazards, visit temblor.net.

    In this report, we discuss the ongoing earthquake sequence on the island of Hokkaido, Japan. Below is a map that shows the epicenter for the mainshock, an earthquake with a magnitude M = 6.6. This map shows the coastline and active faults. There are over 700 aftershocks plotted here.

    1
    Figure 1: Regional seismicity map showing earthquake epicenters from the past 30 days. Faults are in red.

    The major source of earthquakes in Japan are the numerous plate boundary fault systems, which include subduction zones, “forearc sliver” strike slip faults, and a collision zone (another form of convergent plate boundary). The figure below is from the American Geophysical Union blog “Trembling Earth,” written by Dr. Austin Elliot. Great earthquakes, quakes with M ≥ 8.0, in the 20th century include the 1923 Great Kantō subduction earthquake and the 1944 and 1946 Tōnankai and Nankai subduction earthquakes. Subduction zones are convergent plate boundaries where an oceanic plate is subducting beneath a continental or oceanic plate. These events helped shape the earth science programs in Japan, especially regarding efforts to learn about subduction zone processes. The 2011 M 9.1 Tohoku-oki subduction zone earthquake generated a trans-pacific tsunami and reminded the public that their efforts to be resilient are well founded.

    2
    Figure 2: Oblique view showing the configuration of the plate boundaries in the region of Japan.

    The various plates and how they are configured is very complicated in Japan and we learn more about them every year. The recent M 6.6 Sapporo earthquake along the southern part of Hokkaido, Japan was also associated with a plate boundary, but not a subduction zone. In northern Japan, the North America/Okhotsk plate is moving southwestward and converging towards the Amuria/Eurasia plate. This plate motion leads to northeast-southwest oriented compression. This compression has led to the formation of tectonic deformation and thrust faults involved in the Hidaka Collision Zone. Collision zones are convergent plate boundaries where two continental plates are converging. An analogical collision zone is the collision of the India and Eurasia plates that form the Himalayas. The map below shows a generalized view of the geologic rocks in Japan, along with the location of different plate boundary faults (Van Horne et al., 2013). The Hidaka Collision Zone is labeled on the map. I placed a blue star in the location of the M 6.6 earthquake.

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    Figure 3: Geologic map of Japan showing the plate boundaries and key tectonic features including the Hidaka Collision Zone (Van Horne et al., 2016).

    Ground Shaking

    The M 6.6 Sapporo earthquake generated significant ground shaking and triggered landslides across the region. There are 3 main factors that control the intensity of ground shaking from earthquakes: (1) the magnitude of the earthquake, (2) the distance from the earthquake, and (3) the earth materials between the earthquake and one’s location. Earthquake magnitude is a measure of the amount of energy released during an earthquake, while intensity is a measure of how strongly the ground shakes (and how damaging the shaking is). It makes sense that when there is a larger magnitude, there is the potential for stronger shaking and a higher intensity. The magnitude does not change with distance, but intensity does. The further away from the earthquake source, the less shaking one might observe.

    Here is a figure prepared using the J-SHIS Japan Seismic Hazard Information website. The color represents Peak Ground Acceleration, a measure of ground shaking. The units are also in g, an acceleration, where g = 9.8/m2. If ground shaking is about 1 g, there is possibly enough energy to throw materials into the air (like rocks, cars, or buildings). The symbols represent locations where instruments made these acceleration measurements. Between symbols, the color represents an estimate of the ground shaking at those locations. Note that one site near the earthquake epicenter has a measured acceleration of 1.5 g!

    4
    Figure 4: Ground shaking map showing Peak Ground Acceleration (PGA) represented by color.

    Many governments and non-governmental organizations prepare estimates of seismic hazard so that people can ensure their building codes are designed to mitigate these hazards. The Global Earthquake Model (GEM) is an example of our efforts to estimate seismic hazards, though on a global scale. Temblor.net uses the Global Earth Activity Rate (GEAR) model to prepare estimates of seismic hazard at a global to local scale (Bird et al., 2015). Each of these models incorporate earthquake information from different sources including, but not limited to, fault slip rates, records of prehistoric earthquakes, historic seismicity, and strain of the Earth’s crust as measured using Global Positioning System (GPS) observations.

    Below is a map prepared using the temblor.net app. The rainbow color scale represents the change of a given earthquake magnitude, for a given location, within the lifetime of a person. The temblor app suggests that this region could have an earthquake of M 7.1 in a human lifetime.

    5
    Figure 5: Global Earthquake Activity Rate map for this region of the northwest Pacific. Warmer colors represent regions that are more likely to experience a larger earthquake than the regions with cooler colors. Seismicity from the past is shown and the location of the M 6.6 earthquake is located near the blue teardrop symbol.

    Landslides

    There are many different ways in which a landslide can be triggered. The first order relations behind slope failure (landslides) is that the “resisting” forces that are preventing slope failure (e.g. the strength of the land) are overcome by the “driving” forces that are pushing this land downwards (e.g. gravity). The ratio of resisting forces to driving forces is called the Factor of Safety (FOS). We can write this ratio like this:

    FOS = Resisting Force / Driving Force

    When FOS > 1, the slope is stable and when FOS < 1, the slope fails and we get a landslide. The illustration below shows these relations. Note how the slope angle α can take part in this ratio (the steeper the slope, the greater impact of the mass of the slope can contribute to driving forces).

    6
    Figure 6: Landslide force balance diagram showing how driving and resisting forces balance for a stable slope.

    Some factors that change this ratio include rainfall, over steepening of the slope, undercutting of the base of the slope, and earthquakes. There are other factors as well.

    Japan recently experienced the most severe Typhoon in decades, which resulted in significant rainfall. When rain water infiltrates into the earth, that water can fill the spaces between soil particles and rock cracks so that the water pressure pushes apart these particles or rocks. If this pressure is large enough, the strength of the material (a resisting force) becomes weaker and there can be a landslide. Even if there is not enough reduction in resisting force, the strength of the material is still potentially weaker.

    Landslide ground shaking can change the Factor of Safety in several ways that might increase the driving force or decrease the resisting force. Keefer (1984) studied a global data set of earthquake triggered landslides. The plot presented here shows that that larger earthquake magnitudes (horizontal axis) can result in landslides across a larger area.

    7
    Figure 7: Spatial extent of landslide triggering by earthquakes relative to earthquake magnitude (Keefer, 1984).

    As a result of the M 6.6 Sapporo earthquake, there were a large number of slope failures in the epicentral region. These landslides have covered many buildings and unfortunately have trapped many dozens of people within the debris. We will learn more about this in the coming days as search and rescue teams respond to this disaster.

    There have been many videos posted online, possibly the best ones from Nippon Hōsō Kyōkai (NHK), Japan’s national public broadcasting organization. NHK also acquired the best aerial videos from the inundation of the 2011 Tohoko-oki earthquake and tsunami. There have also been some excellent comparisons between pre-landslide and post-landslide aerial imagery.

    Here is another spectacular view of some of these triggered landslides here.

    Below is a pair of images that presents a comparison of the landscape from before and after the earthquake. These come from social media here.

    8
    9
    Figure 8: A comparison of imagery from before and from after the earthquake. The earthquake triggered landslides in the second image are identified in this photo by the areas of exposed brown colored soil.

    These landslides appear to be failures within the soil mantle of the hillsides. While these landslides were triggered by the earthquake, it is highly likely that the water content from the Typhoon decreased the Factor of Safety prior to the earthquake. It is possible that without this preceding Typhoon, the slope failures might have been less catastrophic.

    Active Faults in Hokkaido

    There are a number of active crustal faults in southern Hokkaido, Japan. One may view the location of these faults on the Japan Seismic Hazard Information Station (J-SHIS) website here. In addition, estimates for seismic hazard are also placed on that website. For example, the National Seismic Hazard Map for Japan is included there. There are various versions of this map, but the most useful version is the map that shows the chance that an area in Japan will experience earthquake ground shaking at least JMA 6, for the next 30 years. The Japan Meteorological Agency Seismic Intensity Scale (JMA) is an intensity scale with a range of 0 – 7, with 7 being the highest intensity, the strongest ground shaking. To give us an idea about how strong the shaking might be for an earthquake with a JMA 6 intensity, this is what a person might experience: “Impossible to keep standing and to move without crawling.”

    Below is a map that is based upon the J-SHIS website. We plot USGS earthquake epicenters from this earthquake sequence as circles colored relative to their depth with circle size relative to earthquake magnitude. Included in this map are also the active fault sources, shown as red rectangles and black lines. The two active faults in the region are different parts of the Ishikari-teichi-toen fault (the main part and the southern part). Based upon expert knowledge, these faults have the potential to produce an M 7.2 and M 7.1 earthquake for the main part and southern part, respectively. Combined, these faults may produce an M 7.9 earthquake. The USGS fault plane solution (moment tensor) is shown, along with a legend that helps one interpret this diagram. More can be found about these “beach balls” here.

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    Figure 9: Earthquake shaking potential and active fault map. Warmer colors (red) represent areas that are more likely to shake strongly (minimum JMA 6) compared to the less warm colors (yellow). Active faults are shown as red rectangles or black lines.

    This M 6.6 earthquake was about 33 km (20 miles) deep, deeper than the active crustal faults in the National Seismic Hazard Map. The earthquake was a thrust or reverse earthquake (oriented as a result of northeast-southwest compression, consistent with the orientation of the Hidaka Collision Zone).

    This M 6.6 earthquake has changed the stresses within the crust surrounding the earthquake. The amount of this stress change is moderate, especially when compared with the amount of stress that is typically released during an earthquake. We label the faults in the above map that may or may not have an increased amount of stress (the Ishikari fault system).

    This change in stress is called a change in “static coulomb stress” and a paper that discusses the fundamental factors controlling these stress increases is from Lin and Stein (2004). There is software available to the public from the USGS to perform these calculations. This software is called “Coulomb 3” and is available online here. An introduction to this software and the physics behind the calculations can be found in Stein (2003).

    An earthquake occurs when the stress is greater than the strength of the rock. Rocks can have strengths that range dozens of Mega Pascal (1,000,000 Pa = 1 MPa). When earthquakes slip they release stress on the order of several to a dozen MPa. In order for an earthquake to trigger another earthquake due to these changes in stress, the triggered earthquake fault needs to have a pre-existing level of stress that is somewhat close to failure.

    Dr. Shinji Toda has calculated the change in static coulomb stress as a result of the M 6.6 earthquake. They prepared two different analyses. (1) Dr. Toda first used a computer model to estimate the increased stress that could be observed on a generic fault parallel to the M 6.6 earthquake. (2) Then Dr. Toda used a computer model to estimate what the increase in stress that might be observed on a known active fault near the M 6.6 earthquake epicenter.

    For both analyses, the process begins by choosing a fault geometry for the source earthquake fault (e.g. the M 6.6 earthquake fault). This includes the size (length and width) and the geometry (angle dip beneath horizontal and compass orientation) of the fault. The analysis also requires information about how much the fault slipped along this fault, which controls the magnitude of these stress changes. Finally assumptions need to be made about the material properties of the crust (i.e. the rheology), which controls the spatial distribution and extent of these stress changes. Dr. Toda used the mainshock focal mechanism and seismic moment, centered in the hypocenter.

    One may then calculate the change in stress on generic receiver faults in the region surrounding the source fault. Receiver faults are the faults that may have triggered earthquakes from an increase in stress. Dr. Toda calculated the change in stress for two potential source fault orientations. The figure below shows that there are regions of increased stress (red) and decreased stress (blue). The units for these stress changes are bar, a measure of force. 1 bar = 100,000 Pascal (Pa), or 0.1 MPa. If there were a fault in the red region, and this fault were parallel to the source fault, those faults have the potential to be triggered by this change in stress. Faults that are parallel to the source fault and are located in blue areas, they would have a decrease in stress, inhibiting the possibility of a triggered earthquake.

    11
    Figure 10: Static coulomb stress change imparted by the M 6.6 earthquake onto generic receiver faults that are parallel to the source fault. Red represents regions of increased stress and blue represents regions of decreased stress.

    The next step is to input the fault geometry for a “receiver” fault based upon known active faults in the National Seismic Hazard Map database. Dr. Toda selected a fault similar to the southern part of the Ishikari fault in the active fault database from Japan. The map below shows the configuration of this experiment (north is up, units on both axes is kilometers), including the shoreline and fault geometry. The source fault is the blue rectangle in the center of the map. The receiver fault is the series of small rectangles that compose a larger rectangle. Notice how the receiver fault overlaps the source fault.

    12
    Figure 11: Static coulomb stress change imparted by the M 6.6 earthquake onto an active fault with a known geometry. Red represents regions of increased stress and blue represents regions of decreased stress.

    The figure here shows that there is a strong decrease in stress (-0.5 bar) in the area of the fault near the epicenter and a modest increase in stress (0.15 bar) further to the north. Drs. Toda and Stein hypothesize that the net effect probably inhibits failure on this receiver fault. The Ishikari fault is capable of producing an earthquake M > 7 and this fault did not rupture during the M 6.6 earthquake. So, those who live in the region would benefit from continuing their efforts to mitigate the earthquake hazards that they are faced with.

    Here is another perspective of these data. The view is from the southeast looking into the Earth.

    13
    Figure 12: Low Angle Oblique Stress Changes: Static coulomb stress change imparted by the M 6.6 earthquake onto an active fault with a known geometry. Red represents regions of increased stress and blue represents regions of decreased stress.
    References:

    Bird, P., Jackson, D. D., Kagan, Y. Y., Kreemer, C., and Stein, R. S., 2015. GEAR1: A global earthquake activity rate model constructed from geodetic strain rates and smoothed seismicity, Bull. Seismol. Soc. Am., v. 105, no. 5, p. 2538–2554, DOI: 10.1785/0120150058

    Keefer, D.K., 1984. Landslides caused by earthquakes. GSA Bulletin 95, 406-421

    Lin, J., and R. S. Stein (2004), Stress triggering in thrust and subduction earthquakes and stress interaction between the southern San Andreas and nearby thrust and strike-slip faults, J. Geophys. Res., 109, B02303, doi:10.1029/2003JB002607

    Stein, R.S., 2003. Earthquake conversations, Scientific American, v. 288, no. 1, p. 72-79

    Travasarou, T., Bray, J.D., Abrahamson, N.A., 2003. Empirical attenuation relationship for Arias Intensity. Earthquake Engineering and Structural Dynamics 32, 1133-1155

    Van Horne, A., Sato, H., Ishiyama, T., 2017. Evolution of the Sea of Japan back-arc and some unsolved issues in Tectonophysics, v. 710-711, p. 6-20, http://dx.doi.org/10.1016/j.tecto.2016.08.020

    More information about the tectonics in this region can be found here.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

    Earthquake Network is a research project which aims at developing and maintaining a crowdsourced smartphone-based earthquake warning system at a global level. Smartphones made available by the population are used to detect the earthquake waves using the on-board accelerometers. When an earthquake is detected, an earthquake warning is issued in order to alert the population not yet reached by the damaging waves of the earthquake.

    The project started on January 1, 2013 with the release of the homonymous Android application Earthquake Network. The author of the research project and developer of the smartphone application is Francesco Finazzi of the University of Bergamo, Italy.

    Get the app in the Google Play store.

    3
    Smartphone network spatial distribution (green and red dots) on December 4, 2015

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States
    1

    The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.

    Watch a video describing how ShakeAlert works in English or Spanish.

    The primary project partners include:

    United States Geological Survey
    California Governor’s Office of Emergency Services (CalOES)
    California Geological Survey
    California Institute of Technology
    University of California Berkeley
    University of Washington
    University of Oregon
    Gordon and Betty Moore Foundation

    The Earthquake Threat

    Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.

    Part of the Solution

    Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.

    Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.

    System Goal

    The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.

    Current Status

    The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.

    In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.

    This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.

    Authorities

    The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.

    For More Information

    Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
    rdegroot@usgs.gov
    626-583-7225

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

     
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