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  • richardmitnick 11:21 am on July 5, 2019 Permalink | Reply
    Tags: "Southern California M 6.4 earthquake stressed by two large historic ruptures", , QCN Quake-Catcher.net, ,   

    From temblor: “Southern California M 6.4 earthquake stressed by two large historic ruptures” 

    1

    From temblor

    July 4, 2019
    Ross S. Stein, Ph.D., and Volkan Sevilgen, M.Sc., Temblor, Inc.

    The site of the 4th of July shock was stressed by the great 1872 Owens Valley quake and the 1992 Landers quake. Their overlapping stress lobes may have raised the stakes for this region.

    Citation: Stein, R. S., and Sevilgen, V., (2019), Southern California M 6.4 earthquake stressed by two large historic ruptures, Temblor, http://doi.org/10.32858/temblor.034

    A Magnitude 6.4 earthquake struck the remote southern California high desert today, a region which has been the site of several moderate earthquakes over the past 30 years (Hauksson and Unruh, 2007), and tends to exhibit swarm-like behavior. Based on its aftershocks, the quake appears to have ruptured two perpendicular faults, one right-lateral (whichever side you are on, the other moves to the right), and the other left lateral, as shown below.

    1
    Temblor app map of the mainshock and its first two hours of aftershock suggests that two orthogonal faults have ruptured together. The inferred sense of slip is represented by the half arrows.

    The Eastern California Shear Zone lights up

    The quake lies west of Searles Valley and east of Ridgecrest, near the Naval Air Warfare Center on China Lake. This is a region of diffuse shear and extension, as indicated by the myriad of small distributed faults, and is part of the so-called ‘Eastern California Shear Zone.’ It also lies close to a geothermally active region that heats and locally thins the crust. While the San Andreas is the major fault system that accommodates the Pacific-North America plate motion, the Eastern California Shear Zone plays a secondary role, and so, in fact, the plate boundary spans the entire girth of California.

    2
    The ‘Eastern California Shear Zone,’ within which the 4th July shock struck, rivals the San Andreas for great quakes, producing an M~7.6 shock in 1872, an M=7.3 shock in 1992, and an M=7.1 shock in 1999.

    Two quakes gang up in Ridgecrest

    We calculate that two large earthquakes, the 26 March 1872 M~7.6 Owens Valley shock, and the 29 June 1992 M=7.3 Landers shock, permanently imparted stress to the site of today’s shock, perhaps increasing the likelihood of earthquakes in this region over others.

    3
    The site of the July 4th shock was likely brought closer to failure in the 1872 M~7.6 shock. Notice that the (red) stress trigger zones of the this 148-year-old quake are all seismically active today, whereas the (blue) stress shadows are generally devoid of shocks.

    The more recent 1992 M 7.3 Landers shock was followed by the Ridgecrest earthquakes of M 5.4 in August 1995, and an M 5.8 in September 1995 (Hauksson et al., 1995). These earthquakes perhaps indicate that stress imparted by the Landers earthquake immediately brought this area closer to failure, and so the 1995 events might be regarded as remote aftershocks.

    4
    The 4th July earthquake lies at the northern edge of a stress trigger lobe of the 1992 Landers shock. Together, the 1872 and 1992 earthquakes increased the stress at the 4th July epicenter by about 0.25 bars, a small but significant amount.

    In 2005, Shinji Toda and his colleagues used the 1992 Landers stress changes and the pattern of seismicity to make a retrospective forecast of seismicity, below. The forecast is in red, the observed quakes that struck are in blue. Because of its voluminous background seismicity and the imparted stress, one can see that the site of the 4th July shock was indeed forecast for a high quake rate.

    5
    The 4th July quake struck where the background rate of shocks is high, and where stress was transferred by the 1992 earthquake.

    What’s Next?

    Our preliminary calculation, below, suggests that parts of the Garlock, Black Mountain, and Panamint Valley Faults were brought closer to failure by the 4th July quake. Fortunately, all of these are in remote, lightly populated regions.

    6
    Coulomb 3.3 calculation of stress transferred by the 4th July shock to the surrounding region and major faults. Here we use a simple source based on the moment tensor (geometry, sense of slip, and size) of the earthquake, as determined by the USGS.

    Citation: Stein, R. S., and Sevilgen, V., (2019), Southern California M 6.4 earthquake stressed by two large historic ruptures, Temblor, http://doi.org/10.32858/temblor.034

    References

    Egill Hauksson, Kate Hutton, Hiroo Kanamori, Lucile Jones, James Mori, Susan Hough, and Glenn Roquemore (1995), Preliminary Report on the 1995 Ridgecrest Earthquake Sequence in Eastern California, Seismological Research Letters, 66 (6), 54-60, doi.org/10.1785/gssrl.66.6.54

    Hauksson, E., and J. Unruh (2007), Regional tectonics of the Coso geothermal area along the intracontinental plate boundary in central eastern California: Three-dimensional Vp and Vp /Vs models, spatial-temporal seismicity patterns, and seismogenic deformation, J. Geophys. Res., 112, B06309, doi:10.1029/2006JB004721.

    Stein, R.S., Earthquake Conversations, Scientific American, vol. 288, 72-79, January issue, 2003. Republished in: Our Ever Changing Earth, Scientific American, Special Edition, v. 15 (2), 82-89, 2005.

    Toda, S., Stein, R. S., Richards-Dinger, K. & Bozkurt, S. Forecasting the evolution of seismicity in southern California: Animations built on earthquake stress transfer. J. Geophys. Res. 110, B05S16 (2005) https://doi.org/10.1029/2004JB003415

    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 10:48 am on June 6, 2019 Permalink | Reply
    Tags: A unique opportunity to drill and instrument the seismogenic zone of large megathrust earthquakes, , , , , QCN Quake-Catcher.net, ,   

    From temblor: “Osa Peninsula, Costa Rica: A unique opportunity to drill and instrument the seismogenic zone of large megathrust earthquakes” 

    1

    From temblor

    June 4, 2019
    Jason Patton

    1
    The past month of earthquakes in Costa Rica with boundaries show that the Osa peninsula is unusually close to the Middle America Trench, and has a very high quake rate.

    A unique opportunity exists on the Osa peninsula, in southern Costa Rica to drill and instrument a locked but mature segment of the Middle America Subduction Zone. This section of the Middle America Subduction Zone has suffered large (Mw=7.2-7.4) earthquakes in 1853, 1904, 1941 and 1983. With an average recurrence interval of roughly 40 years, the timing is now right to drill, instrument and record data of unrivalled importance before, during and after the next megathrust earthquake in this region. Because the subduction of young, rejuvenated and thickened lithosphere, the megathrust surface is unusually shallow. As a consequence, the plate interface beneath the peninsula lies just 4-8 km beneath land. This shallow depth and record of large quakes makes drilling possible and instrumentation fruitful.

    2
    Cross-section with no vertical exaggeration showing the close proximity of the Osa peninsula to the megathrust surface of the Cocos Plate.

    Geodetic observations indicate that the subduction interface is locked beneath the peninsula (Kobayashi et al., 2014) (Figure 3). The surface geology has been mapped to a large extent based on continuous shoreline exposures and observations in bedrock rivers that incise in response to rapid uplift. These uplift rates have been quantified for the Quaternary (the past million years) using marine terraces and their associated sedimentary cover. A series of trench-parallel, landward-dipping reverse faults have been mapped on the peninsula, which could represent splay faults and fluid conduits, similar to those imaged offshore Nankai, Japan, site of a great earthquake sequence in 1944-1946. All of this makes the Osa Peninsula an ideal site to compare with very important results that are currently obtained in the Nankai Trough. Since the trench is only 15-30 km from the SW coastline of Osa Peninsula, submarine cables with seafloor instrumentation, power and data transmission can be deployed and tight to borehole instrumentation, at a much lower cost than in other subduction zones.

    Drilling and instrumenting the hole with seismometers, strainmeters, tiltmeters, fluid samplers and fluid flow meters, among other instruments, would establish the relationship between surface geology, subsurface, upper plate structure, surface deformation and the characteristics of the locked interface. We noted that there are signals only detectable by borehole observatories. The integration of these datasets would be an unprecedented opportunity to relate continuous processes such as strain accumulation and seismic slip with the longer-term evolution of the margin that manifests as upper plate deformation, and permanent uplift. This will be a chance to contribute to the international efforts carried out all over the world, as part of a global network of observatories to understand the genesis of large and destructive earthquakes, to help estimate the seismic hazards and therefore contribute to the reduction of their potential damage.

    Large efforts have been invested in trying to drill to the source of large subduction earthquakes. Since most of these seismogenic zones are located offshore and deeper than current ‘non-riser’ and ‘riser’ drilling technology, very few subduction zone candidates exist where this goal can be achieved. Even at these offshore locations, the cost and time required to drill them are extremely large. Furthermore, strong ocean currents can cause an interruption in drilling operations for a large part of the year and therefore require the drilling vessel to transit to the site many times, which further increases the cost. On the other hand, drilling a 6-8 km hole on land would cost roughly $10-$30 million USD and could be completed in less than 6 months.

    We welcome inquiries from scientists and institutions for such an ambitious yet discounted project. Resources from ICDP, national funding agencies, and potentially other foundations could be leveraged to take advantage of this unique tectonic and temporal opportunity.

    References:

    Bangs, N. L., K. D. McIntosh, E. A. Silver, J. W. Kluesner, and C. R. Ranero (2015), Fluid accumulation along the Costa Rica subduction thrust and development of the seismogenic zone, J. Geophys. Res. Solid Earth, 120, 67–86, doi:10.1002/2014JB011265.

    Kobayashi, D., P. LaFemina, H. Geirsson, E. Chichaco, A. A. Abrego, H. Mora, and E. Camacho (2014), Kinematics of the western Caribbean: Collision of the Cocos Ridge and upper plate deformation, Geochem. Geophys. Geosyst., 15, 1671–1683, doi:10.1002/2014GC005234.

    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 10:15 am on June 3, 2019 Permalink | Reply
    Tags: "El Salvador Earthquake: A Moderate Event in An Area of Extreme Seismic Risk", , , , QCN Quake-Catcher.net, ,   

    From temblor: “El Salvador Earthquake: A Moderate Event in An Area of Extreme Seismic Risk” 

    1

    From temblor

    Posted on June 1, 2019 by Tiegan Hobbs
    Tiegan Hobbs, Ph.D., Postdoctoral Hazard Scientist (@THobbsGeo), and Ross S. Stein, Ph.D., Temblor, Inc.

    Because of its offshore location and moderate depth, Thursday’s shock did little damage. But many indications suggest that El Salvador will not stay so lucky for long. This event also highlights the increasing number of large extensional earthquakes: a global trend with important hazard implications.

    1
    A photo by Twitter user Daniel (@dfvegacom) showing the calm after the earthquake in El Salvador.

    At 03:03 am local time on Thursday morning, a strong earthquake ruptured off the west coast of El Salvador on the Pacific side of Central America. It was felt in southern Mexico, Guatemala, Honduras, Nicaragua, and Costa Rica, with a maximum reported intensity of about Level VI (strong shaking). The quake awakened many residents of the nearby city of La Libertad, less than an hour’s drive south of the capital city of San Salvador. But fortunately, the shaking is likely to damage only poorly built structures. Because of its moderate depth and offshore location, no tsunami was produced and little liquefaction or land-sliding is expected.

    2
    Thursday’s M 6.6 earthquake just off the coast of El Salvador was felt in surrounding countries: Mexico, Guatemala, Nicaragua, and Costa Rica.

    Waiting For El Salvador’s ‘Big One’ in the Red Zone

    While this event has no reported damage or injuries so far, El Salvador has among the highest seismic risks in the world. What does that mean, exactly? Hazard refers to the probability of earthquakes occurring, but risk refers to the likelihood of suffering losses from that hazardous event. Both El Salvador and Guatemala are recognized by the Global Earthquake Model Foundation as having a very high potential for losses due to a high likelihood of earthquakes occurring compounded by buildings and population centers that are highly susceptible to damage. So, this week’s earthquake was a gentle reminder of what could be in store for this small country.

    3
    The Global Earthquake Model Foundation assesses seismic risk around the world. El Salvador and Guatemala are both ominously high. (Silva et al., 2018)

    Two Deep Tensional Earthquakes in One Week

    As with the M=8.0 Peru earthquake from earlier this week, Thursday’s M=6.6 El Salvador earthquake was also a relatively deep tensional rupture. That means it occurs within the subducting slab, rather than on the interface between the slab and the over-riding continental plate. In this part of Central America, tensional events occur relatively frequently at this depth range (Correa-Mora et al., 2009). This includes a M=7.3 in 1982 and M=7.7 in 2001, which, combined, killed almost 2,000 people.

    Conflicting views of seismic hazard in Central America

    Although the GEM model and the Global Earthquake Activity Rate model (Bird et al., 2015), used by Temblor and shown in the first figure, both suggest high risk for El Salvador and Guatemala, Correa-Mora et al., (2009) argue that the subduction zone in this region may be too ‘weak’ (slippery) to generate large megathrust earthquakes. These are the kinds of events that are usually associated with great damage, and which can generate tsunami if they occur near the ocean floor. Correa-Mora and coauthors suggested that although there is a great deal of energy being released through earthquakes in the subduction zone region here, they are probably mostly from these tensional events. Nevertheless, earthquakes can be deadly regardless of their mechanism. The 1556 Huaxian earthquake in China occurred in an extensional rift environment, and yet it is the single deadliest earthquake on record, claiming 830,000 lives (Liu et al., 2011).

    Is the Rate of Large Global Tensional Earthquakes Growing?

    In addition to this week’s two major extensional (also called ‘normal’ or tensional) earthquakes, the last couple of years have seen other strong tensional events: the September 2017 M=7.1 Puebla earthquake in Mexico City, the November 2018 M=7.1 Anchorage earthquake in Alaska, and the February 2019 M=7.5 Ecuador earthquake. But is the apparent increase in extensional events real?

    4
    A map of tensional earthquakes with magnitude 7 and above, since 2005. They are distributed mainly in the ‘Ring of Fire, around the Pacific Ocean. Mapped using GeoMapApp.

    Generally speaking, we detect more earthquakes with time because networks, detection algorithms, and computing power are all improving. However, the number of large extensional events appears to increase with time at a greater rate than either thrust events or combined thrust and strike-slip events. The rate of increase is 0.01 magnitude units per year when normalized to all non-extensional earthquakes, and 0.02 when compared to only thrust events. This means that (1) there are more large tensional earthquakes than there were before, and (2) the occurrence of thrust events is actually decreasing slightly.

    6
    9

    The proportion of normal events is increasing with time. The ratio of extensional events to all other types of events (top) and to only thrust events (bottom), inclusive from 1976-2018 (Global CMT Project). Only M>7 earthquakes considered. The lines show a linear regression (fitting), with the corresponding equations and regression coefficients in the top left. A clear upward trend is observed, although a larger increase is occurring relative to thrust events. This means that the rate of large thrust events is actually decreasing with time.

    It’s possible that, because extensional earthquakes are sometimes quite deep, this apparent increased frequency of extensional events is just due to improved seismic networks. Additional work will be required to determine how compelling this result is. However, if it is real then it is astounding! These events occur because the subducting slab is being pulled apart as it is dragged into the mantle by suction. Is that suction force increasing with time, or does it oscillate? We know that great megathrust earthquakes (Ben-Naim et al., 2013) and strike-slip events (Pollitz et al., 2012) can tend to be clustered in time – perhaps the same is true for extensional intraslab events?

    Aftershocks in Unexpected Places

    7
    The initial aftershocks of the M=6.6 event lie 30-40 km southwest of the mainshock.

    Although Thursday’s M=6.6 earthquake off El Salvador was too far away to have been caused by Sunday’s M=8.0 event in Peru, the El Salvador event did produce its own remarkable aftershock sequence. Early aftershocks are concentrated to the southwest of the mainshock, roughly 30 km away, at a depth of about 35 km. Usually, aftershocks are distributed around the edge of the region that slipped during the mainshock, rather than being clustered in only one direction. This may be due to the rupture propagating (unzipping) towards the southwest, concentrating seismic energy in that direction, or possibly related to a tear or bump in the subducting slab that makes this region more susceptible. By studying cases like this one, scientists can better understand where and when aftershocks will strike in the aftermath of much larger earthquakes.

    References

    Ben‐Naim, E., Daub, E. G., & Johnson, P. A. (2013). Recurrence statistics of great earthquakes. Geophysical Research Letters, 40(12), 3021-3025.

    Bird, P., Jackson, D. D., Kagan, Y. Y., Kreemer, C. & Stein, R. S. (2015). GEAR1: A Global Earthquake Activity Rate Model Constructed from Geodetic Strain Rates and Smoothed Seismicity. Bull Seis. Soc. Am.105(5), 2538-2554.

    Correa-Mora, F., DeMets, C., Alvarado, D., Turner, H. L., Mattioli, G., Hernandez, D., … & Tenorio, C. (2009). GPS-derived coupling estimates for the Central America subduction zone and volcanic arc faults: El Salvador, Honduras and Nicaragua. Geophysical Journal International, 179(3), 1279-1291.

    Liu, M., Stein, S., & Wang, H. (2011). 2000 years of migrating earthquakes in North China: How earthquakes in midcontinents differ from those at plate boundaries. Lithosphere, 3(2), 128-132.

    Pollitz, F. F., Stein, R. S., Sevilgen, V., & Bürgmann, R. (2012). The 11 April 2012 east Indian Ocean earthquake triggered large aftershocks worldwide. Nature, 490(7419), 250.

    V. Silva, D. Amo-Oduro, A. Calderon, J. Dabbeek, V. Despotaki, L. Martins, A. Rao, M. Simionato, D. Viganò, C. Yepes, A. Acevedo, N. Horspool, H. Crowley, K. Jaiswal, M. Journeay, M. Pittore (2018). Global Earthquake Model (GEM) Seismic Risk Map (version 2018.1). DOI: 10.13117/GEM-GLOBAL-SEISMIC-RISK-MAP-2018.1, https://maps.openquake.org/map/global-seismic-risk-map/

    GEM Profile for El Salvador: https://downloads.openquake.org/countryprofiles/SLV.pdf

    USGS Event Pages

    https://earthquake.usgs.gov/earthquakes/eventpage/us70003t2n

    https://earthquake.usgs.gov/earthquakes/eventpage/us2000ar20/

    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 9:17 am on May 29, 2019 Permalink | Reply
    Tags: A magnitude-8.0 quake shook deep below the Amazon Rainforest in Peru causing extensive liquefaction and shaking from Colombia to Chile., , QCN Quake-Catcher.net, ,   

    From temblor: “Deep earthquake in Peru is felt along the length of South America: More to follow?” 

    1

    From temblor

    May 28, 2019
    Tiegan Hobbs, Ph.D., Postdoctoral Seismic Risk Scientist (@THobbsGeo)

    A magnitude-8.0 quake shook deep below the Amazon Rainforest in Peru, causing extensive liquefaction and shaking from Colombia to Chile.

    A powerful Mw 8.0 earthquake shook Peru at 2:41 a.m. local time on Sunday, May 26, 2019, from an epicenter within the Reserva Nacional Pacaya-Samiria of the Amazon Rainforest. Although it was felt from Colombia to Chile, this deep event (about 110 kilometers) did not generate a tsunami and only two casualties have been reported (AP). At least 26 people are injured in Peru and Ecuador. Casualties were limited due to the remote location of the epicenter and the depth of the quake.

    1
    The 26 May 2019 M=8.0 event was slightly larger and about 440 kilometers to the southeast of a M=7.5 earthquake that occurred in Ecuador on 22 Feb 2019.

    Damage and liquefaction expected in the Amazon.

    2
    This map, produced by the United States Geological Survey, shows estimated Mercalli shaking intensity (colored contour lines from maximum of orange level VIII) and liquefaction probability (colored contours with maximum dark purple representing a greater than 20% chance of liquefaction).

    The United States Geological Survey (USGS) now routinely produces maps of probable landslide and liquefaction. According to the shaking and topography of the area, this event is predicted to cause widespread and/or severe liquefaction affecting approximately 74,000 people. It is not predicted to cause an extensive landslide, though aerial surveys showed at least one landslide in the jungle.

    3
    Road damage in the Cajamarca Region from Twitter (@Crisanris).

    Peru resident Cristina Andrade (@crisanris) reported road damage due to ground displacements from this event and aerial photography shows a landslide in the lush jungles of this region (Reuters). Little information has emerged about the extent of the destruction, despite incoming footage from the firefighters of Peru (@BomberosPE) showing rubble lining the streets of Yurimaguas, the town nearest the epicenter, in Alto Amazonas. Emergency teams and politicians have been converging on the affected areas to lead the response.

    4
    Landslide as a result of Sunday’s earthquake, as reported to Reuters (@Univ_inenglish).

    Not the first deep earthquake in this area

    Events like this one, which occur deep within Earth’s crust and rupture under extensional forces, are different than usual subduction zone earthquakes. This earthquake occurred entirely within the subducting Nazca Plate, which is being pulled apart as it is sucked deeper into Earth’s mantle. We call this type of earthquake an “intraplate event: occurring within the plate. More often, subduction zone earthquakes are “interplate” events, in which earthquakes occur on the boundary between two plates. These events, like the 2016 M=7.8 earthquake in Pedernales, Ecuador (http://temblor.net/earthquake-insights/ecuador-earthquakes-what-happened-and-what-is-next-986/), tend to be shallower and therefore are closer to population centers and the ocean floor. They’re thus more likely to cause tsunamis and significant damage.

    5
    This figure, modified from Leyton et al., 2009, shows the difference between interplate events, which occur between two plates, and intraplate events, like Sunday’s Mw 8.0 event in Peru.

    Questions may arise as to whether Sunday’s Mw 8.0 earthquake in Peru was related to a February Mw 7.5 event in Ecuador. That event was also a deep, extensional intraplate quake. While these two earthquakes were very similar and happened within a few months of one another, they were upwards of 400 kilometers apart. Therefore, the static stress change from the February event was too small to have triggered Sunday’s event.

    Sunday’s quake, like most deep earthquakes, is likely to be relatively depleted in aftershocks [e.g. Wiens & McGuire, 1995]. So far, no events with magnitude greater than 2.5 have been reported by the USGS for that area.

    References

    pic.twitter.com/miV5ak8Gf6

    pic.twitter.com/3bFW9JqfE9

    USGS Event Pages

    https://earthquake.usgs.gov/earthquakes/eventpage/us60003sc0/executive

    (https://earthquake.usgs.gov/earthquakes/eventpage/us60003sc0/ground-failure/summary

    https://earthquake.usgs.gov/earthquakes/eventpage/us2000jlfv/executive

    Leyton, F., Ruiz, J., Campos, J., & Kausel, E. (2009). Intraplate and interplate earthquakes in Chilean subduction zone: A theoretical and observational comparison. Physics of the Earth and Planetary interiors, 175(1-2), 37-46.

    Wiens, D. A., & McGuire, J. J. (1995). The 1994 Bolivia and Tonga events: Fundamentally different types of deep earthquakes?. Geophysical research letters, 22(16), 2245-2248.

    Other News Sources

    https://www.eluniversal.com.mx/english/magnitude-8-earthquake-hits-peru (Reuters)

    https://www.apnews.com/3b12f5abea604f19a5ad36d700d090b1 (AP)

    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 1:47 pm on May 20, 2019 Permalink | Reply
    Tags: , Large Earthquake in Papua New Guinea re-ruptures major fault in just 19 years: More to follow?, QCN Quake-Catcher.net, ,   

    From temblor: “Large Earthquake in Papua New Guinea re-ruptures major fault in just 19 years: More to follow?” 

    1

    From temblor

    May 19, 2019
    Tiegan Hobbs, Ph.D., Postdoctoral Seismic Risk Scientist at Natural Resources Canada (@THobbsGeo)

    A magnitude-7.5 quake broke the same fault that produced a magnitude-8.0 quake in 2000, an extraordinarily short recurrence time that also broke all our rules.

    A major earthquake struck eastern Papua New Guinea (PNG) on Tuesday, May 14th at 22:58 local time. No injuries have been reported, although shaking from this Mw 7.5 earthquake was felt up to 250 km (150 mi) away from the epicenter. The maximum shaking intensity (the so-called ‘Modified Mercalli level VII’) would have been sufficient to cause considerable damage in poorly built houses which are common in the region.

    1
    Map showing the location of the 14 May 2019 Mw 7.5 Papua New Guinea Earthquake, as well as the M=7.1 quake on the other side of the country, which struck just a week beforehand.

    According to Dr. Baptiste Gombert, postdoctoral researcher at Oxford University, the event “occurred on the left-lateral Weitin fault [WF in the map below], a major structure of the New Ireland”. ‘Left-lateral’ means that whatever side you are on, the other side moved to the left. This fault marks the boundary between the North and South Bismarck microplates.

    Beyond the Weitin Fault, this region has “every type of plate boundary” according to Dr. Jason Patton from the California Geological Survey and Adjunct Professor at Humboldt State University. For example, compression and shear between the Pacific and Australian Plates results in subduction along the New Britain Trench, rifting in the Woodlark Basin in addition to the observed strike-slip activity in the area of Tuesday’s quake.

    2
    Modified from Holm et al., [2019], this map shows the regional tectonics. Looking like broken shards of glass, there is a complex interaction of possibly inactive subduction from the north and south, along with rifting, subduction, thrusting, and strike slip faults in between. The USGS moment tensor (beachball) from Tuesday’s Mw 7.5 event (blue star) suggests left-lateral motion on the Weitin Fault between the North and South Bismarck Plates. The event rattled residents of New Ireland (NI), the elongate island through which the Weitin Fault runs.

    First Ever Measurement of Onshore Repeated Rupture

    What makes this event so exciting, though, is that it’s not the first major earthquake in this location. A Mw 8.0 event in the year 2000 resulted in up to 11 m of slip along a 275-km-long (165 mi) fault, with 20 aftershocks with magnitude greater than 5 [Tregoning et al., 2001]. The proximity of this week’s hypocenter to the larger quake 19 years ago had Dr. Sotiris Valkaniotis, geological consultant, wondering if they ruptured the same portion of the fault. With some quick work processing satellite imagery, Dr. Valkaniotis produced what is believed to be the first recording of repeated on-land rupture of a fault.

    ________________________________________

    And we have slip! Co-seismic displacement on Weitin Fault, New Ireland, #PNG after the strong M7.5 May 15 2019 #earthquake. Displacement analysis from optical image correlation using #Sentinel2 images from @CopernicusEU and #MicMac. Repeat rupture on the same fault as 2000! pic.twitter.com/5PFZdfOdPj

    — Sotiris Valkaniotis (@SotisValkan) May 16, 2019
    ________________________________________

    The figure in the above tweet, reproduced below, shows several meters of offset across the fault for both earthquakes. It’s preliminary, but it suggests that this fault is extremely active. For reference, Dr. Gombert describes the Weitin Fault as having a strain rate that is approximately 4 times that of the San Andreas in California. That’s important, because it presents a rare opportunity to study an entire seismic cycle from one large earthquake to the next in under 20 years—which appears to be unprecedented. These observations could help answer important questions about whether earthquakes repeatedly rupture the same patch, and what tends to initiate these events. In many places, such as the Cascadia Subduction Zone with its roughly 500-year recurrence period, this is simply not possible.

    3
    Surface displacements in the North-South direction for the most recent Mw 7.5 event and the 2000 Mw 8.0 event on the Weitin Fault. Measurements made using optical correlation of Sentinel-2 and Landsat-7 satellite data.

    2000 Mw 8.0 Event Triggered Large Nearby Earthquakes

    Within 40 hours of the 16 November 2000 earthquake on the Weitin Fault, which was itself preceded by a 29 October 2000 Mw 6.8 foreshock, two events of magnitude 7.4 and 7.5 were recorded nearby [Park & Mori, 2007]. The events were found to be consistent with static stress triggering from the mainshock, and with a previous observation of Lay and Kanamori [1980] that earthquakes in this part of the world tend to occur in doublets: two large mainshocks that are close in space and time rather than the typical mainshock-aftershock sequence. It begs the question “will there be more?”

    Triggering of Aftershocks From This Sequence?

    Three strong aftershocks have so far struck near the mainshock: two Mw 5.0 events on Tuesday May 14th and Thursday May 16th, and a Mw 6.0 on Friday May 17th. Although we don’t yet know the type of faulting that occurred in these events, we can evaluate how the Mw 7.5 mainshock may have promoted them. A Coulomb Stress calculation shows that the epicentral locations of these events experienced stress loading of 112, 4, and 2 bars, respectively, assuming a similar fault geometry. This is well in excess of a 1 bar triggering threshold, suggesting that all three of these fault locations were brought closer to failure by the mainshock. In the map below, regions of red shading indicate areas prone to aftershocks – extending along an over 100 km swath of New Ireland. Given that the previous event in 2000 was able to trigger relatively large earthquakes on the Weitin [Geist and Parsons, 2005], the coming days and weeks could bring more large events to the region.

    Without doubt, the data from this earthquake sequence will illuminate the stress evolution of this rapidly straining strike-slip fault and serve as a helpful natural laboratory for understanding similar strike-slip systems which are slower to reveal their mysteries.

    5
    Stress change caused by the 14 May 2019 mainshock (green star), for faults with similar orientation. Red indicates areas of positive Coulomb stress change (up to 5 bars), and cyan shows regions with negative stress change (to -5 bars). The two Mw 5.0 and one Mw 6.0 aftershocks (white diamonds) experienced Coulomb stress loading upwards of the triggering threshold.

    Tsunami Warnings for Papua New Guinea and the Solomon Islands

    Strike-slip faults, like the Weitin and the San Andreas in California, generate dominantly horizontal motions, and so are fortunately unlikely to launch large tsunami unless they trigger undersea landslides. Some 9 minutes after the earthquake started, the Pacific Tsunami Warning Center assessed a tsunami threat for regions within 1000 km of the quake: mainly Papua New Guinea and the Solomon Islands. The threat was called off within about an hour and a half, with wave heights reaching less than 0.3 m (about a foot).

    It is important to remember in the coming days and weeks, however, that aftershocks are also capable of producing dangerous tsunami. Following the Mw 8.0 New Ireland earthquake on the same fault in 2000, runups from the mainshock and triggered aftershocks were greater than 3 meters (9 feet) in some locations [Geist and Parsons, 2005]. This was partly due to the thrust mechanism of the aftershocks, which causes greater vertical displacement and therefore larger potential for tsunami. Because many populations in this region live close to the coast, the safest strategy is self-evacuation. This means that if you feel shaking that is strong or long, head to high ground without waiting to be told.

    Read More:

    USGS reports

    https://earthquake.usgs.gov/earthquakes/eventpage/us70003kyy/executive

    https://earthquake.usgs.gov/earthquakes/eventpage/us70003l05/executive

    https://earthquake.usgs.gov/earthquakes/eventpage/usd000a1im/executive

    https://earthquake.usgs.gov/earthquakes/eventpage/us70003mus/executive

    Tsunami warnings

    https://www.tsunami.gov/events/PHEB/2019/05/14/19134000/1/WEPA40/WEPA40.txt

    https://www.tsunami.gov/events/PHEB/2019/05/14/19134000/3/WEPA40/WEPA40.txt

    Social Media:

    https://twitter.com/SotisValkan/status/1129069849131401216 (imagery based surface displacement measurement comparison)

    Geist, E. L., & Parsons, T. (2005). Triggering of tsunamigenic aftershocks from large strike‐slip earthquakes: Analysis of the November 2000 New Ireland earthquake sequence. Geochemistry, Geophysics, Geosystems, 6(10).

    Holm, R. J., Tapster, S., Jelsma, H. A., Rosenbaum, G., & Mark, D. F. (2019). Tectonic evolution and copper-gold metallogenesis of the Papua New Guinea and Solomon Islands region. Ore Geology Reviews, 104, 208-226.

    Lay, T., & Kanamori, H. (1980). Earthquake doublets in the Solomon Islands. Physics of the Earth and Planetary Interiors, 21(4), 283-304.

    Park, S. C., & Mori, J. (2007). Triggering of earthquakes during the 2000 Papua New Guinea earthquake sequence. Journal of Geophysical Research: Solid Earth, 112(B3).

    Tregoning, P., McQueen, H., Lambeck, K., Stanaway, R., Saunders, S., Itikarai, I., Nohou, J., Curley, B., Suat, J. (2001). Progress Report on Geodetic Monitoring of the November 16, 2000 – New Ireland Earthquake. Australian National University, Research School of Earth Sciences, Special Report 2001/3. http://rses.anu.edu.au/geodynamics/tregoning/RSES_SR_2001-3.pdf

    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 10:58 am on May 15, 2019 Permalink | Reply
    Tags: "Two damaging tremors highlight the Philippines’ coast-to-coast earthquake problem", 100% of the Philippines is earthquake country., A tragedy and a success story that followed, , QCN Quake-Catcher.net, , , The first quake was a near-miss of Manilla, The mysterious Philippine Trench, Unlike California   

    From temblor: “Two damaging tremors highlight the Philippines’ coast-to-coast earthquake problem” 

    1

    From temblor

    May 9, 2019
    Chris Rollins, Ph.D.
    Michigan State University

    Unlike California, 100% of the Philippines is earthquake country. Two damaging and deadly earthquakes late last month served as a reminder of this.
    1
    The 22 and 23 April 2019 Philippines earthquakes against a backdrop of the past month of M≥4.5 shocks, which strike on the many active faults that lace—and formed—the archipelago. At the locations of last month’s quakes, the earthquake magnitude likely in one’s lifetime is over M=7, or about 10-20 times larger than the quakes recently experienced.

    The first quake was a near-miss of Manilla

    On April 22 just after 5 PM local time, a magnitude 6.1 earthquake struck less than 85 km (50 mi) from the Philippine capital of Manila, in the provinces of Zambales and Pampanga on the northern island of Luzon. In footage that went viral around the world (link), the shaking ejected water out of a rooftop swimming pool atop a Manila skyscraper. But back on Earth, the earthquake killed 18 people and caused widespread damage in the epicentral region. Although the epicenter was in Zambales, shaking intensities and damage were worse in neighboring Pampanga, much of which sits on soft sediments that amplify shaking, as reported by the Philippine Institute of Volcanology and Seismology (PHIVOLCS). This is a recurring theme in earthquake hazard: we typically settle near water, often on unconsolidated sediments recently deposited by water flow. This is a good call except when an earthquake strikes.

    2
    Damage in the April 22 M=6.1 earthquake. Photo courtesy of Al Jazeera.

    Luzon is no stranger to earthquakes, as it is surrounded on the west and east by subduction trenches and sliced down the middle by the Philippine Fault, a major left-lateral strike-slip fault (whichever side you are on, the other side has moved to the left), with about the same character and slip rate as the San Andreas Fault. The fault likely partners with the subduction zones to accommodate different components of the regional tectonic strain in a “slip partitioning” system.

    3
    The left-lateral Philippine Fault and right-lateral San Andreas Fault are remarkably similar. They have the same slip rate (~25 mm/yr or 1 in/yr), length, straightness, secondary faults, and each has a history of strong, damaging earthquakes. The Temblor Earthquake Score for San Francisco is 77; in Manila, the Philippine capital, it is 88. Manila is the most densely populated city in the world (12 million residents in the metropolitan area, 22 million in the greater urban area).

    A tragedy and a success story that followed

    In 1990, the Philippine Fault ruptured in a M=7.7 strike-slip earthquake that killed over 1,600 people on Luzon. That earthquake – which provides a possible parallel for future earthquakes on the San Andreas and other strike-slip faults around the world – also appears to have squeezed the magma chamber feeding nearby Mt. Pinatubo and hastened its catastrophic 1991 eruption, the second largest of the 20th century. The volcano reawakened immediately after the M=7.7 shock, and then steadily increased in seismicity and steam eruptions until PHIVOLCS and the USGS jointly announced a likely eruption and called for imminent evacuations. Twelve hours later, Pinatubo erupted, with the warning having saved thousands of lives. This was one of science, collaboration, and diplomacy’s finest hours. It is an ideal we continue to strive for today.

    4
    Many of the famous photos of the 1991 Pinatubo eruption show a textbook mushroom cloud – and are actually from a comparatively minor eruption three days before the cataclysmic VEI 6 finale. This photo, courtesy USGS, is of the finale.

    For its part, the earthquake on April 22 appears to have struck on a strike-slip fault parallel to, but well to the west of, the Philippine Fault. It did strike only 15 km (10 mi) from Pinatubo, so it could conceivably have been influenced by magmatic activity there. The reverse is unlikely, however: PHIVOLCS reported no sign of increased activity at Pinatubo after April 22.

    The mysterious Philippine Trench

    That’s more than enough tectonic unrest for one country (particularly one undergoing rapid development in the early 21st century), but it’s only one piece of the story in the Philippines. On the east side of the country lies the Philippine Trench, along which the Philippine Sea Plate is subducting westward beneath the archipelago. The Philippine Sea Plate’s motion is notoriously difficult to constrain because it is a fully “oceanic plate” with few islands on which to place GPS receivers to track its motion. Further, all of its boundaries are subduction zones, a rarity. But the convergence rate along the Philippine Trench probably exceeds 10 cm/yr (4 in/yr), faster than those in Japan and Alaska, and about three times faster than the Cascadia subduction zone in the Pacific Northwest. This means that the earthquake loading process is very rapid, and so great quakes should be frequent.

    5
    Damage in the April 23 M=6.5 Visayas earthquake, courtesy of CNN.

    The Philippine Trench has produced a handful of M>7 earthquakes in the 20th century, and on April 23, it ruptured in a M=6.4 thrust earthquake beneath the island of Samar. This followed on the heels of the April 22 quake in Luzon by less than 24 hours, and although 48 people were injured, fortunately no one was killed. The April 23 quake occurred at around 45 kilometers (25 miles) depth, which may have resulted in milder shaking than had it struck closer to the surface. (This may also have been true in the 2018 M=7.1 Anchorage, Alaska earthquake, which was a different kind but also occurred at 45 km depth and resulted in no deaths).

    Was the second quake triggered by the first?

    With two M>6 earthquakes striking in less than 24 hours, were they connected in some way? There are two ways this could work: 1) static stress transfer, via the bending of the Earth in the April 22 event, or 2) dynamic triggering, where the waves from the April 22 M=6.1 event bump the April 23 fault towards failure. We can rule out static stress transfer: the two earthquakes occurred 575 km apart (350 miles, the distance from LA to San Francisco), well outside the range of significant stress change from a M=6.1 earthquake. Dynamic triggering is more elusive: the waves from the April 22 event were not felt more than 100 km (60 miles) away, one-sixth of the interevent distance; but the 1992 M=7.3 Landers, California earthquake and the 2002 M=7.9 Denali Fault earthquake did trigger seismicity at much greater distances.

    A ‘smoking gun’ for this case would be if there was an uptick in seismicity or creep on the April 23 fault immediately after the waves from the April 22 event passed. This is difficult to pin down both because the April 23 event was rather deep and because it struck beneath the rugged and sparsely populated center of Samar, where the growing PHIVOLCS seismic network is understandably still sparse. Remember, though, that the April 23 event occurred in a stress regime featuring a subducting plate coming in faster than those in Japan and Alaska. That could generate an earthquake anytime, especially a M=6.4, and history shows that it does.

    The pair is reminiscent of the much larger recent pair in Mexico: The 2017 M=8.2 Tehuantepec shock was followed 12 days later and 600 km away by the M=7.2 Puebla shock, which felled 38 buildings in Mexico City. In previous work, we found that it is unlikely that the two were causally related. The time difference in the Philippines case is much shorter, but quake rates there are much higher, and so the probability of a link seems similarly low. PHIVOLCS came to the same conclusion, and in a timely manner, immediately after the second quake.

    6
    Earthquakes and faults line all sides of the Philippines. Figure from Wong et al. [2014].

    More to come

    These two earthquakes served as a reminder that the tectonic strain and the seismic hazard in the Philippines come from all sides, and fast. The Cotabato Trench to the south produced the Philippines’ deadliest earthquake in 1976, and the Manila Trench to the northwest poses a tsunami hazard to southeast Asia, coastal China and Hong Kong. The country is at risk.

    References

    Bautista, B.C., Bautista, L.P., Barcelona, E.S., Punongbayan, R.S., Laguerta, E.P., Rasdas, A.R., Ambubuyong, G., Amin, E.Q., and Stein, R.S. (1996), Relationship of regional and local structures to Mount Pinatubo activity, in R. S. Punongbayan and C. G. Newhall (Eds.), The 1991-1992 eruption of mount Pinatubo, Philippines, 351-370.

    Hill, D.P., et al. (1993), Seismicity Remotely Triggered by the Magnitude 7.3 Landers, California Earthquake, Science 260(5114), https://science.sciencemag.org/content/260/5114/1617.

    Prejean, S.G., Hill, D.P., Brodsky, E.E., Hough, S.E., Johnston, M.J.S., Malone, S.D., Oppenheimer, D.H., Pitt, A.M., and Richards-Dinger, K. B. (2004), Remotely Triggered Seismicity on the United States West Coast Following the Mw7.9 Denali Fault Earthquake, Bull. Seis. Soc. Am., 94(6B), https://doi.org/10.1785/0120040610.

    Smoczyk, G., Hayes, G., Hamburger, M., Benz, H., Villasenor, A., and Furlong, K. (2010), Seismicity of the Earth 1900-2012: Philippine Sea Plate and Vicinity, USGS Open-File Report 2010-1083, https://doi.org/10.3133/ofr20101083M.

    Wong, I., Dawson, T., and Dober, M. (2014), Evaluating the Seismic Hazards in Metro Manila, Philippines, 14th World Conference on Earthquake Engineering (14WCEE).

    Ye, L., Lay, T., and Kanamori, H. (2012), Intraplate and interplate faulting interactions during the August 31, 2012, Philippine Trench earthquake (Mw 7.6) sequence, Geophys. Res. Lett., 39, L24310, doi:10.1029/2012GL054164.

    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 9:15 am on April 30, 2019 Permalink | Reply
    Tags: "Ten times more earthquakes now detected in Southern California", , , , QCN Quake-Catcher.net, ,   

    From temblor: “Ten times more earthquakes now detected in Southern California” 

    1

    From temblor

    April 29, 2019
    Ross S. Stein, Ph.D., Temblor

    What did they do?

    In a study published this month in Science, Zachary Ross and Egill Hauksson (both from Caltech), Daniel Trugman (Los Alamos National Laboratory) and Peter Shearer (Scripps Institution of Oceanography) were able to increase the number of recorded southern California earthquakes during 2010-2017 from 180,000 to 1.8 million. They did this by recovering all the quakes that stuck down to a magnitude of 0.29, whereas in the original catalog, only quakes larger than magnitude 1.7 had been reliably recovered. The relationship between earthquake size and frequency obeys a ‘power-law distribution,’ which means that when you drop down one magnitude unit, you get 10 times more quakes.

    How did they do it?

    They employed a method called ‘template matching’. Template matching takes advantage of the similar waveforms recorded at seismometers for quakes located very close together. Each quake was compared to 248,000 template earthquakes, making this is an enormously computer-intensive process. So, they harnessed an array of 200 NVIDIA graphic processing units. NVIDIA’s are designed for video gaming and for self-driving cars, so this is a special kind of scientific dividend. Then, they more precisely located all the earthquakes using a method called ‘double-difference relocation.’ Both methods have been used for a decade or so, but never on so large a data set. The new catalog is now freely available to all researchers (scedc.caltech.edu), a great gift to seismologists around the world.

    2
    Here is an example of the dazzling detail of the relocated seismicity (colored by depth) in the new catalog, which I annotated. Because most of the seismicity at depth lies to the northeast of the fault at the ground surface, the faults must be inclined 8-9° to the northeast, consistent with earlier studies (Fattaruso et al, 2014).

    Did they discover remote aftershocks of an M=7.2 mainshock up to 300 km (180 mi) away?

    In the panel on the right below, sites where the quake rate is higher in the week after the 2010 M=7.2 El Mayor-Cucapah (Baja California) earthquake are red, while sites where the rate is lower are white. The authors declare these are aftershocks, but in fact, their job is to prove it. This would not be unprecedented, as remote triggering following other large shocks has been widely reported (Hill et al., 1993; Brodsky et al., 2000; Prejean et al., 2004; Velasco et al., 2008; Pollitz et al., 2012). But the difference is that the new study bases its findings exclusively on very small (Magnitude<1.0) quakes.

    3
    The ‘Noise’ plot was kindly provided by the authors; the ‘Signal’ plot comes from their paper, with the blue aftershock zone boundary added here. Sites with no reliable rate change are grey.

    On the left panel above is another ‘week after vs. week before’ comparison provided by Zachry Ross, but not centered in the earthquake, so presumably this is just random quake rate variability. I’ve inscribed a blue line around the apparent (mostly red) aftershock zone, which extends twice as far from the mainshock as had been visible before their new catalog was created. Aftershocks promoted by the permanent stress changes in the earth should extend to about 100-135 km, and so the authors ascribe the more distant shocks to dynamic triggering carried by the seismic waves, which reach 300 km away within about 2 minutes from the time the quake begins; within about an hour, those waves will have encircled the globe and will have dissipated, if not disappeared, in southern California.

    Here, below, is another figure in their paper that I have annotated, showing the quake rate relative to the preceding year collapsed on to a line with distance from the epicenter. The quakes within about 135 km or twice the fault length, are consistent with static stress triggering. But for the next 100 km, the quake rate does not decay, which is not what one would expect if they were caused by the seismic wave propagation, which diminishes in amplitude as it propagates away from the rupture, just as ripples diminish in amplitude and spread out as they expand after one throws a stone into a pond. If there is a decay, it is obscured by noise.

    4
    The aftershocks the authors attribute to remote dynamically triggered events exhibit a rate 2-4 times higher in the week after the mainshock than in the preceding year.

    In the next figure below, I compare the authors’ aftershock plot with their plot of seismicity density for the entire catalog period, 2008-2017. If the red quakes are indeed aftershocks, then they should not be correlated with the event density. That’s because aftershock locations should be most influenced by the epicenter and fault rupture. But here, instead, the aftershocks locate just where the long-term seismic rate is highest. It’s almost as if the location of the mainshock doesn’t matter. How could that be so?

    5
    Annotated versions of the figures in Ross et al. (2019). The seismicity density (the number of quakes in each 2 km x km cell) is on the left, and the elevated quake rate after the 2010 mainshock is on the right.

    Here are two possible explanations for this conundrum:

    • Since the event density plot contains the 2010 aftershocks, the two plots are not independent. An event density plot with the first week, or year, after the M=7.2 shock removed would make them nearly independent. I asked the authors if they could provide it, but they chose not to. Irrespective, the highest aftershock density will be near the (yellow) fault rupture, from the U.S.-Mexico border to the south. But the correlation extends ~200 km northwest of that, so I suspect the correlation will remain regardless.

    • If the correlation between longterm event density and aftershocks is real, it would mean that the places which preferentially respond to dynamic triggering are those with very high local seismicity rates, not those with a particular fault geometry or distance from the epicenter. The amplitude and character of the seismic waves would be less important than the sensitivity of certain fault locations to shaking. This would be new and exciting new.

    So, are the remote aftershocks a discovery or a mirage?

    Here is what the authors, or any researchers, would need to do to prove that these events are aftershocks: At least some aftershocks should be triggered as the seismic waves move past those locations in the first few minutes, and no aftershocks at all can strike until the surface waves arrive. Further, the one attribute that distinguishes aftershocks from all other shocks is that their occurrence rate decreases with time in a very particular way: the quake rate decays with 1/time (e.g., 10 hr after the mainshock, the quake rate is 1/10th of its rate in the first hour, 100 hr after the mainshock, the quake rate is 1/100th of its rate in the first hour, etc.). This is called Omori decay in honor of its discovery in 1894 by the Japanese seismologist, Fusakichi Omori, who also came to San Francisco to study the great 1906 earthquake. If the red quakes do not exhibit Omori decay, they are not aftershocks. Another case of tiny, dynamically triggered earthquakes were falsified by these tests (Felzer and Brodsky, 2006; Richards-Dinger et al., 2010).

    If these really are aftershocks, and if they really are correlated with the background seismicity rate, we are going to learn something new and important about how the Earth works.

    References

    Emily E. Brodsky, Vassilis Karakostas, and Hiroo Kanamori, A New Observation of Dynamically Triggered Regional Seismicity: Earthquakes in Greece Following the August, 1999 Izmit, Turkey Earthquake, Geophys. Res. Let., 27, 2741-2744.

    Laura A. Fattaruso, Michele L. Cooke, and Rebecca J. Dorsey (2014), Sensitivity of uplift patterns to dip of the San Andreas fault in the Coachella Valley, California, Geosphere, 10, 1235–1246, doi:10.1130/GES01050.1

    Karen R. Felzer & E. E. Brodsky (2006), Decay of aftershock density with distance indicates triggering by dynamic stress, Nature, 441, 735–738, doi:10.1038/nature04799

    David P. Hill, P. A. Reasenberg, A. Michael, W. J. Arabaz, G. Beroza, D. Brumbaugh4, J. N. Brune, R. Castro, S. Davis, D. dePolo, W. L. Ellsworth, J. Gomberg, S. Harmsen, L. House, S. M. Jackson, M. J. S. Johnston, L. Jones, R. Keller, S. Malone, L. Munguia, S. Nava, J. C. Pechmann, A. Sanford, R. W. Simpson, R. B. Smith, M. Stark, M. Stickney, A. Vidal, S. Walter, V. Wong, J. Zollweg (1993), Seismicity remotely triggered by the Magnitude 7.3 Landers, California, earthquake, Science, 260, doi: 10.1126/science.260.5114.1617

    Stephanie K. Prejean, Hill, D. P., Brodsky, E. E., Hough, S. E., Johnston, M. J. S., Malone, S. D., Oppenheimer, D. H., Pitt, A. M., and Richards-Dinger, K. B. (2004), Remotely triggered seismicity on the United States west coast following the Mw 7.9 Denali Fault earthquake, Bull. Seism. Soc. Am., 94, S348-S359.

    Keith Richards-Dinger, R.S. Stein, R.S., and S. Toda (2010), Decay of aftershock density with distance does not indicate triggering by dynamic stress, Nature, 467, 583-586, doi:10.1038/nature0940

    Zachary E. Ross, Daniel T. Trugman, Egill Hauksson, and Peter M. Shearer (2019), Searching for hidden earthquakes in southern California, Science 10.1126/science.aaw6888.

    Velasco, Aron A., Hernandez, S., Parsons, T., and Pankow, K. (2008). Global ubiquity of dynamic earthquake triggering, Nature Geoscience, 1, 375-379.

    Fred F. Pollitz, R. S. Stein, V. Sevilgen, and R. Bürgmann (2012). The 11 April 2012 East Indian Ocean earthquake triggered large aftershocks worldwide, Nature, 490, 250-253.

    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 3:56 pm on March 5, 2019 Permalink | Reply
    Tags: , , Earthquake hazards, Geophysicists at Caltech have created a new method for determining earthquake hazards by measuring how fast energy is building up on faults in a specific region and then comparing that to how much is , , QCN Quake-Catcher.net, , The method also allows for an assessment of the likelihood of smaller earthquakes. If one excludes aftershocks the probability that a magnitude 6.0 or greater earthquake will occur in central LA over , They applied the new method to the faults underneath central Los Angeles and found that on the long-term average the strongest earthquake that is likely to occur along those faults is between magnitud, They find that the crust beneath Los Angeles does not seem to be being squeezed from south to north fast enough to make such an earthquake quite as likely, When one tectonic plate pushes against another elastic strain is built up along the boundary between the two plates. The strain increases until one plate either creeps slowly past the other or it jerk   

    From Caltech: “Fast, Simple New Assessment of Earthquake Hazard” 

    Caltech Logo

    From Caltech

    1
    Credit: Juan Vargas, Jean-Philippe Avouac, Chris Rollins / Caltech

    March 04, 2019

    Contact
    Robert Perkins
    (626) 395‑1862
    rperkins@caltech.edu

    Geophysicists at Caltech have created a new method for determining earthquake hazards by measuring how fast energy is building up on faults in a specific region, and then comparing that to how much is being released through fault creep and earthquakes.

    They applied the new method to the faults underneath central Los Angeles, and found that on the long-term average, the strongest earthquake that is likely to occur along those faults is between magnitude 6.8 and 7.1, and that a magnitude 6.8—about 50 percent stronger than the 1994 Northridge earthquake—could occur roughly every 300 years on average.

    That is not to say that a larger earthquake beneath central L.A. is impossible, the researchers say; rather, they find that the crust beneath Los Angeles does not seem to be being squeezed from south to north fast enough to make such an earthquake quite as likely.

    The method also allows for an assessment of the likelihood of smaller earthquakes. If one excludes aftershocks, the probability that a magnitude 6.0 or greater earthquake will occur in central LA over any given 10-year period is about 9 percent, while the chance of a magnitude 6.5 or greater earthquake is about 2 percent.

    A paper describing these findings was published by Geophysical Research Letters on February 27.

    These levels of seismic hazard are somewhat lower but do not differ significantly from what has already been predicted by the Working Group on California Earthquake Probabilities. But that is actually the point, the Caltech scientists say.

    Current state-of-the-art methods for assessing the seismic hazard of an area involve generating a detailed assessment of the kinds of earthquake ruptures that can be expected along each fault, a complicated process that relies on supercomputers to generate a final model. By contrast, the new method—developed by Caltech graduate student Chris Rollins and Jean-Philippe Avouac, Earle C. Anthony Professor of Geology and Mechanical and Civil Engineering—is much simpler, relying on the strain budget and the overall earthquake statistics in a region.

    “We basically ask, ‘Given that central L.A. is being squeezed from north to south at a few millimeters per year, what can we say about how often earthquakes of various magnitudes might occur in the area, and how large earthquakes might get?'” Rollins says.

    When one tectonic plate pushes against another, elastic strain is built up along the boundary between the two plates. The strain increases until one plate either creeps slowly past the other, or it jerks violently. The violent jerks are felt as earthquakes.

    Fortunately, the gradual bending of the crust between earthquakes can be measured at the surface by studying how the earth’s surface deforms. In a previous study [JGR Solid Earth] (done in collaboration with Caltech research software engineer Walter Landry; Don Argus of the Jet Propulsion Laboratory, which is managed by Caltech for NASA; and Sylvain Barbot of USC), Avouac and Rollins measured ground displacement using permanent global positioning system (GPS) stations that are part of the Plate Boundary Observatory network, supported by the National Science Foundation (NSF) and NASA. The GPS measurements revealed how fast the land beneath L.A. is being bent. From that, the researchers calculated how much strain was being released by creep and how much was being stored as elastic strain available to drive earthquakes.

    This research was supported by a NASA Earth and Space Science Fellowship.

    See the full article here .

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network projectEarthquake 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

    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


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

    Caltech campus


    Caltech campus

     
  • richardmitnick 9:58 am on February 26, 2019 Permalink | Reply
    Tags: "Seismic warning to India: A shock strikes just north of Delhi", , , , , , QCN Quake-Catcher.net, ,   

    From temblor: “Seismic warning to India: A shock strikes just north of Delhi” 

    1

    From temblor

    February 25, 2019
    By Aron Mirwald, M.Sc.
    Ross Stein, Ph.D., Temblor, Inc.

    On 20 February 2019, a magnitude 4 earthquake struck 50 km (30 mi) north from the megacity, Delhi. A magnitude 4 earthquake is not large. If it occurs nearby, it can be felt, and may generate some damage, but it is almost never fatal. This earthquake was no exception: shaking has been reported to be weak to moderate. So, what is interesting about it? Actually, there is a lot to be learned from small, seemingly unimportant events like this. Let us use this earthquake as a means to explore the seismic risk in India.

    1
    This portion of a new map from the GEM Foundation shows the expected cost of earthquake damage relative to the cost of construction, averaged over time, everywhere on Earth. The Himalayan Foothill Thrust region lights up in a band of yellow-orange high risk. The risk is the product of a very high seismic hazard and an extremely high population density. Pakistan and Nepal are also seen to be at very high risk, followed by greater Kabul in Afghanistan.

    Crushing into Eurasia

    We know from GPS observations that the Indian plate is moving 16-18 millimeters per year towards the Eurasian plate (Bilham & Ambraseys, 2005). It is pushed, rather forcefully, below the Eurasian plate. This movement has resulted in the creation of the beautiful Himalayas. But it has also resulted in a thrust-zone, where many great earthquakes occur. In this zone, the two plates are interlocked most of the time. Since the plate is pushing from behind, the stress builds up until it is strong enough to overcome fault friction. Then, very large earthquakes can occur.

    3
    India has been in a slow-motion crash into Asia for 40 million years, as attested to by 500 years of historical reports of great earthquakes, with events striking principally along India’s northern frontier. Some 400 million people live in the Ganges Plain (bright white area), just south of the frontier, in India and Bangladesh. Graphic by Volkan Sevilgen.

    At the thrust-zone between the Indian and Eurasian plate, at least three earthquakes with a magnitude larger than 8 have occurred in medieval times (Bilham, 2009). The recurrence time of this kind of earthquakes is unknown, but it is speculated that earthquakes of similar magnitude are overdue (Bilham & Ambraseys, 2005).

    But, if we take a closer look at last week’s earthquake, it did not occur at the thrust-zone, but further in the south. Actually, there are many earthquakes known to occur far away from the thrust-zone. This could be easily explained, if the Indian plate itself was deformed substantially. But, we know that the rate of deformation along the continent is very low, around 5 millimeters per year (Bilham, 2004). This is too low to explain frequent seismicity.

    The Indian plate is buckling

    The explanation is simple, yet fascinating. The downward bend of the Indian plate beneath the Himalayas has resulted in a ‘flexure’, or bending, of the plate. We can see this in the cross—section south of the thrust-zone. There is first an upward bulge of approximately 450 meters, followed by a smaller depression (Bilham, 2004). Now, we can imagine the plate to be like a wooden stick: it bends before it breaks.

    4
    In this cross-section, North is to the right, and South to the left. The buckling of the Indian plate leads to a bulge south of Delhi, along with shallow tensional quakes, as struck last week. The great earthquakes strike along the thrust fault at right (purple), as well as other sites of concentrated buckling (Bilham, 2009).

    The first part that breaks is usually a weak spot. In tectonic plates such weak spots are often faults, planes where the rock has failed previously due to an earthquake. Weak planes, that were previously stable, will be pushed towards the thrust-zone, and move through the bulge, where the change of flexural stresses can trigger failure and consequently earthquakes.

    Seismic Risk in India

    Now we can put the picture together: Seismic risk in India can be attributed to earthquakes at the thrust-zone below the Himalayas, and to seismicity within the continent due to flexural stresses.

    Delhi, as an example of a vulnerable metropolis, has a history of being affected by both (Iyengar, 2000). There are around 20 seismically active faults in the vicinity of Delhi capable of generating earthquakes. The Mahendraghar–Dehradhun fault, for instance, could produce an earthquake of magnitude 7 (Iyengar & Gosh, 2004). One problem is, that the fast urbanization in Delhi is leading to a rising number of buildings that are helpless even in the face of moderate sized earthquakes (Mittal et. al., 2012).

    India is one of the countries with the most earthquake-related deaths. Just in the past century, over 100.000 people have died due to earthquakes in the country (Bilham, 2009). This number is unlikely to decrease in the future: Its population is growing, and the consequential increase of fatalities is foreseeable (Bilham, 2009).

    5
    India lies in the cluster of countries in the upper right, which have suffered the largest number of large earthquakes and fatalities since the turn of the 19thth century (Bilham, 2009)

    Hope for the best, prepare for the worst

    In their hazard assessment, Nath and Thingbaijam (2012) conclude that the Bureau of Indian Standards underestimates the seismic risk in India and recommend updating the National Building Code. But there is another problem. According to Bilham (2009), constructers often ignore existing building codes. Among the reasons he lists are ignorance of the seismic risk and the engineering solutions to it, people trying to save money, and corruption. He suggests that this could be solved by education. If everybody knew about the fatal consequences of not including earthquake resistant structures, it would occur less frequently.

    Often, action is only taken after the disaster, but that is too late for many. So, this comparatively small earthquake near the megacity should be a reminder to put more effort to raise awareness of the earthquake risk.

    References

    Bilham, Roger. The seismic future of cities. Bulletin of Earthquake Engineering, 2009, 7. Jg., Nr. 4, S. 839.
    Bilham, Roger, et al. Earthquakes in India and the Himalaya: tectonics, geodesy and history. Annals of GEOPHYSICS, 2004.
    Bilham, Roger; AMBRASEYS, Nicholas. Apparent Himalayan slip deficit from the summation of seismic moments for Himalayan earthquakes, 1500–2000. Current science, 2005, S. 1658-1663.
    GEM Global Seismic Risk Map (Silva et al., 2018), https://maps.openquake.org/map/global-seismic-risk-map/
    Iyengar, R. N. Seismic status of Delhi megacity. Current Science, 2000, 78. Jg., Nr. 5, S. 568-574.
    Iyengar, R. N.; GHOSH, Susanta. Microzonation of earthquake hazard in greater Delhi area. Current Science, 2004, 87. Jg., Nr. 9, S. 1193-1202.
    Mittal, Himanshu, et al. Stochastic finite modeling of ground motion for March 5, 2012, Mw 4.6 earthquake and scenario greater magnitude earthquake in the proximity of Delhi. Natural Hazards, 2016, 82. Jg., Nr. 2, S. 1123-1146.
    Nath, S. K.; Thingbaijam, K. K. S. Probabilistic seismic hazard assessment of India. Seismological Research Letters, 2012, 83. Jg., Nr. 1, S. 135-149.

    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 11:52 am on January 24, 2019 Permalink | Reply
    Tags: , , Peru-Chile Trench, QCN Quake-Catcher.net, , Strong shaking from central coastal Chile earthquake, , What does it reveal about the next megathrust shock?   

    From temblor: “Strong shaking from central coastal Chile earthquake: What does it reveal about the next megathrust shock?” 

    1

    From temblor

    January 20, 2019
    Jason Patton

    Jason R. Patton, Ph.D.; Jean Baptiste Ammirati, Ph.D., University of Chile National Seismological Center; Ross Stein, Ph.D.; Volkan Sevilgen, M.Sc.

    “It is clear to many of us that the Coquimbo region has an unusual, increasing seismicity that may be preparing the area for a very large earthquake near the end of the present century.”

    Raul Madariaga, Ecole Normale Superieure (Paris) and Universidad de Chile (Santiago)

    An earthquake located just beneath the subduction zone of the Peru-Chile Trench strongly shook Coquimbo and La Serena, and was felt up to 400 km away in Santiago. This quake struck just north of the edge of the M=8.3 Illapel megathrust earthquake, which launched a destructive tsunami in 2015.

    Deep earthquake was felt broadly

    On 20 January 2019 there was an M=6.7 earthquake along the convergent plate boundary on the west coast of Chile, about the same size as the 1994 Northridge quake in southern California or about the size of an earthquake that might hit the San Francisco Bay area In northern CA. The earthquake was quite deep (53 km, or about 33 miles), so was not as damaging as those CA examples. However, it was broadly felt with over 800 USGS Did You Feel It reports at the time we write this article.

    1
    Reports from the USGS Did You Feel It website survey

    For most earthquakes that have a potential to damage people, buildings, or infrastructure, the U.S. Geological Survey prepares an estimate of these types of damage. The PAGER alert is based on the strength of measured and modeled shaking (explained in greater detail here). For this M=6.7 earthquake PAGER assigns a 43% chance that there will be between 10 and 100 fatalities, and a 53% chance that there will be economic losses between $10 and $100 million (USD).

    The largest city near the earthquake, Coquimbo, was hit by a tsunami in 2015 when the adjacent section of the subduction zone ruptured. Below is a photo taken following the 2015 M=8.3 earthquake and tsunami. There are over 300,000 people in Coquimbo and the nearby city of La Serena that likely experienced strong to severe shaking intensity from the M=6.7 event. We were quite surprised that the M=6.7 actually caused as much damage as it has, especially in comparison with the 2015 M=8.3 earthquake, which shook less despite being about 300 times larger.

    The Chilean Navy (SHOA) alert system worked very well yesterday. The SHOA tsunami alert that was withdrawn about 30 min after the earthquake, once it was clear that this was not a subduction event. During that half hour, several thousand people followed instructions and took evacuation routes until told to return. This is a valuable test-run of tsunami warnings, and a credit to Chile.

    Plate motions: locked or slipping?

    The deep marine trench offshore the west coast of Chile is formed by a subduction zone where the Nazca plate is shoved beneath the South America plate. This megathrust fault has a variety of material properties and structures that appear to control where the plates are locked, and so accumulating stress towards the next large earthquake, and where they are slipping ‘aseismically’ past each other, and so with a low likelihood of hosting a great quake.

    Below is a map that shows the location of plate boundaries in the region. The majority of high hazard is associated with the subduction zone fault.

    2
    Seismic hazard for South America (Rhea et al., 2010). The numbers (“80”) indicate the rate at which the Nazca Plate is subducting beneath South America. 80 mm/yr = 3 in/yr.

    Are you in earthquake country? Do you know what the earthquake hazards are where you live, work, or play? Temblor uses a model like the USGS model to forecast the chance that an area may have an earthquake. Learn more about your temblor earthquake score here.

    These locked zones are generally where megathrust earthquakes nucleate. In Chile, below a depth of about 50 km (~30 miles) the plate interface is not locked (Gardi et al., 2017), so megathrust fault earthquakes are generally shallower than this depth. Earthquakes deeper than this generally occur within the Nazca plate slab, called ‘slab’ earthquakes because they lie are within the subducting slab. Often these slab earthquakes are extensional, as was the 20 January 2019 M=6.7 quake.

    3
    Cross section of the subduction zone that forms the Chile Trench.

    Below is an aftershock map prepared by Jean-Baptise Ammirati at the University of Chile and the Chilean National Seismic Network.

    4
    We have added the arrows to suggest that the aftershock alignment hints at a west-dipping tensional fault.

    Earthquake history along the Peru-Chile trench

    Much of the megathrust has slipped during earthquakes in the 20th and 21st centuries. The historic record of earthquakes is shown in the figure below. The vertical lines represent the size and extent of the earthquake. The largest earthquake ever recorded by seismometers was the 1960 M=9.5 Chile shock that caused widespread damage, triggered landslides, and generated a trans-oceanic tsunami that destroyed the built environment and caused casualties in Hawaii, Japan, and the west coast of the USA (e.g. Crescent City).

    In 1922 there was an M=8.5 earthquake in the region of today’s M=6.7 quake (Ruiz and Madariaga, 2018). According to Dr. Raul Madariaga, this 1922 event was a subduction zone earthquake that generated a trans-oceanic tsunami which caused damage in Japan and launched a 9m (30 feet) wave just north or Coquimbo, Chile. There has not been a large earthquake in the area of the 1922 earthquake in almost a century, a time longer than average when compared to the rest of the subduction zone. Nevertheless, there was a 129-year pause between the 1877 and 2005 events to the north.

    Also remarkable is the apparent northward progression of great quakes with time from the 1922 event, to 1946, 1966, 1995, 2007, and 2014, for a distance of 1200 km (11° of latitude).

    5
    Historic earthquake record (on the left) coincides with the map of the megathrust showing an estimate of where the fault is stuck and where it may be freely slipping. The M=6.7 earthquake epicenter is located near the blue star. Slab earthquakes are labeled with a gray star (e.g. 1997 discussed below).

    The nearby 1997 sequence started from the north and advanced to the south during the
    month of July 1997, until it produced the 15 October Punitaqui 1997 earthquake. Seismologists will monitor this event to see if there is any seismic migration, which is rare.

    Geologists use GPS data, remote sensing data, and physical measurements of the Earth to monitor how the Earth deforms during the earthquake cycle. The observations can be “inverted” to estimate where the fault is locked and where it is slipping. The figure above shows an interpretation of where the subduction zone fault is locked, and where it may be slipping. Note how the M=6.7 earthquake struck in an area where the megathrust may be freely slipping.

    What does it mean?

    The historic record of earthquakes along the subduction zone makes clear that the absence of megathrust earthquakes for almost a century at the location of the M=6.7 event is unusually long. While it is possible that the Coquimbo portion of the megathrust is not fully locked, it would be prudent for those living along the coast of Chile would to practice their earthquake drills and prepare their homes and finances to withstand effects from a future large earthquake.

    Stay tuned to the latest news about earthquake, tsunami, landslide, liquefaction, and other natural hazards by signing up for our free email service here.

    Citation: Patton J.R., Ammirati J.B. ,Stein R.S., Sevilgen V., 2019, Strong shaking from central coastal Chile earthquake: What does it reveal about the next megathrust shock?, Temblor, http://doi.org/10.32858/temblor.012

    References

    Beck, S., Barrientos, S., Kausel, E., and Reyes, M., 1998. Source Characteristics of Historic Earthquakes along the Central Chile Subduction Zone in Journal of South American Earth Sciences, v. 11, no. 2, p. 115-129, https://doi.org/10.1016/S0895-9811(98)00005-4

    Gardi, A., A. Lemoine, R. Madariaga, and J. Campos (2006), Modeling of stress transfer in the Coquimbo region of central Chile, J. Geophys. Res., 111, B04307, https://doi.org/10.1029/2004JB003440

    Métois, M., Vigny, C., and Socquet, A., 2016. Interseismic Coupling, Megathrust Earthquakes and Seismic Swarms Along the Chilean Subduction Zone (38°–18°S) in Pure Applied Geophysics, https://doi.org/10.1007/s00024-016-1280-5

    Rhea, S., Hayes, G., Villaseñor, A., Furlong, K.P., Tarr, A.C., and Benz, H.M., 2010. Seismicity of the earth 1900–2007, Nazca Plate and South America: U.S. Geological Survey Open-File Report 2010–1083-E, 1 sheet, scale 1:12,000,000.

    Ruiz, S. and Madariaga, R., 2018. Historical and recent large megathrust earthquakes in Chile in Tectonophysics, v. 733, p. 37-56, https://doi.org/10.1016/j.tecto.2018.01.015

    Learn more about the plate tectonics in 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

     
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