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  • richardmitnick 10:42 am on May 24, 2019 Permalink | Reply
    Tags: "Monitoring Haiti’s Quakes with Raspberry Shake", , , , Earthquakes, ,   

    From Eos: “Monitoring Haiti’s Quakes with Raspberry Shake” 

    From AGU
    Eos news bloc

    From Eos

    17 May 2019
    By Eric Calais, Dominique Boisson, Steeve Symithe, Roberte Momplaisir, Claude Prépetit, Sophia Ulysse, Guy Philippe Etienne, Françoise Courboulex, Anne Deschamps, Tony Monfret, Jean-Paul Ampuero, Bernard Mercier de Lépinay, Valérie Clouard, Rémy Bossu, Laure Fallou, and Etienne Bertrand

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    A woman displays a Raspberry Shake seismometer. Poor-quality construction, typical of many neighborhoods in Haiti, is visible in the background. A pilot project to create a network of these personal seismometers across Haiti aims not only to provide earthquake data but also to involve citizens in earthquake awareness and hazard mitigation efforts. Credit: E. Calais

    On 12 January 2010, a devastating earthquake put Haiti on the map for many of us who were unaware of the recurrent difficulties that the country has endured over the past decades. The earthquake claimed more than 200,000 lives, and the damage amounted to about $11 billion, close to 100% of the country’s gross domestic product.

    Before the earthquake, Haiti had no seismic network, no in-country seismologist, no active fault map, no seismic hazard map, no microzonation, and no building code. The national seismic network that has emerged since then currently consists of 10 broadband stations (Figure 1) [Seismological Research Letters ], operated and maintained by Haiti’s Bureau of Mines and Energy (BME). Although this network was a significant step in the right direction, it has not proved to be a panacea.

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    Fig. 1. Seismic stations in Haiti (symbols) and seismic activity as reported by the U.S. Geological Survey (white circles) from August 1946 to 14 January 2019. Natural Resources Canada (NRCan) broadband station PAPH (red circle), based in Port-au-Prince, is usually operational. The nine Raspberry Shake stations shown on this map (with their code names) were installed in January 2019 and were operational as of 15 February. The yellow star east of Port-au-Prince indicates the location of the M3.1 earthquake shown in Figure 3. Stations RE7D0, RE87E, and R2ABA, which use Wi-Fi to connect to the Internet, are not observing the radio frequency interference noted by some RS hosts elsewhere who also use Wi-Fi to connect to the Internet. BME is Haiti’s Bureau of Mines and Energy, which operates seismic instruments from two manufacturing companies.

    On 6 October 2018, a magnitude 5.9 earthquake struck northwestern Haiti, causing 17 fatalities and significant damage in the larger cities of the epicentral area. Only one seismic station was operating at the time, a situation that has persisted for several years now. In spite of its continued efforts, it is difficult for the BME to overcome the chronic lack of resources—financial and human—necessary to maintain such a high-technology system.

    This is where Raspberry Shake (RS) comes into play [Anthony et al., 2018 (Seismological Research Letters)]. This organization, founded using a Kickstarter campaign in 2016, provides affordable “personal seismometers” powered by small Raspberry Pi computers. The low cost of an RS station and the ease of installation and maintenance make it possible to imagine a situation in which perhaps as many as 100 citizens, businesses, or schools throughout Haiti would host an RS station.

    To do more than just imagine, we began a pilot project last January, purchasing and deploying nine one-component vertical velocimeters (RS1D) throughout Haiti (Figure 1), four of them additionally equipped with 3-D accelerometers (RS4D). Except for one station located at the BME, all RS hosts are private homes or hotels. We selected these hosts from people whom we knew had quasi-continuous Internet access and electricity, the latter being a major issue in Haiti. This initiative is similar to the Quake Catcher Network [see below] [Cochran et al., 2009 (Seismological Research Letters)], although the latter uses only accelerometers.

    Overcoming Limited Resources

    As a result of resource limitations, seismologists in Haiti are able to provide only limited information to the public or to decision-makers when earthquakes are felt. This reinforces the ill-founded perception that seismic monitoring is of little value, and it keeps the population in the dark about seismic hazard. As a result, citizens and businesses do little to protect themselves from future large events. The lack of reliable information also provides ground for fake seismonews, including the notion that earthquake prediction has already been around for years so that earthquake monitoring is irrelevant.

    Interestingly, however, the public demands reliable information about earthquakes and tsunamis and their associated risks. They ask questions, want to be informed, and want to know how to prepare. Some would even like to be able to help improve earthquake knowledge in Haiti.

    A citizen’s network of small, affordable seismic stations could be a starting place for providing this information. Even though RS instruments would most likely be concentrated in major cities, their redundancy would alleviate inevitable maintenance issues at any single station. Such a network would improve the ability of the Haiti seismic network to detect small-magnitude earthquakes on a continuous basis, resulting in a better understanding of earthquake distribution and fault behavior. In addition, installing seismometers in people’s homes may be a way to initiate a conversation with the population to promote a culture of earthquake safety.

    Setting Up the Network

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    Raspberry Shake setup at station R897D in Jacmel (see Figure 1) uses an RS1D instrument located on the first floor of a public notary’s office, under “made-on-the-spot” wooden protection. The RS station is connected to secure power and to the Internet through an Ethernet cable to the router visible on the windowsill. From left to right are Berthony (technician from the Haiti Bureau of Mines and Energy); Mrs. Beaulieu, who hosts the station; and authors Eric Calais and Steeve Symithe. Credit: E. Calais

    We set about creating our RS network by simply laying an RS instrument on the floor of the quietest first-story room we could find at each location. We connected them to power and Internet utilities, in six cases directly to the router via an Ethernet cable and in three cases via Wi-Fi. We made it clear to the hosts that the RS stations would use very little power and Internet bandwidth but that they should contact us if they suspected any issue. We also told them that they were free to disconnect the RS in case of a problem.

    Several hosts asked whether their RS could serve to predict earthquakes or whether they would sound an alarm if seismic waves were coming. We made it very clear that this was not the case and explained that we were mostly interested in the smaller earthquakes: the ones they never feel but that occur every day.

    “What? There are earthquakes every day in Haiti?” was a common reaction. Yes, indeed, we told our hosts, and knowing where and how big the small quakes are tells us a lot about the future large ones. Many hosts asked how they could see the information. We showed them how to view the helicorder (which records data from the seismometer) from their smartphone or computer on their local network, but often, they were not impressed with the displays. Helicorder output is indeed difficult to read because most squiggles are not earthquakes. Clearly, we need to do more work on how to provide relevant and useful information to RS station hosts.

    First Observations

    Three weeks after the installation of the first RS, we could already make a few observations that will be useful for the next phase of our project and, we hope, for other similar projects elsewhere.

    We have detected many events that occurred less than 100 kilometers from this first RS station. The first one (Figure 2), recorded on 13 January 2019, was later located by the seismological network of the Dominican Republic, which quoted its magnitude as 3.1. We also recorded a sequence of four events in northwestern Haiti the day after we installed another station; these events were not reported by any regional seismic network. Regional events show up very well too, for example, the M5.3 earthquake that struck the Dominican Republic on 4 February 2019. Even the P wave and S wave arrivals of teleseismic (distant) events are recorded, including an M5.6 earthquake that occurred in Colombia on 26 January 2019.

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    Fig. 2. Station R30E2, located in downtown Pétion-Ville, produced Haiti’s first Raspberry Shake station recording of a local earthquake on 13 January 2019. This event was not reported by Haiti’s national seismic network, but it was later reported by the Dominican Republic seismic network as an M3.1 event (yellow star in Figure 1) along the Enriquillo–Presqu’île du Sud fault close to the border between Haiti and the Dominican Republic.

    Noise levels are, of course, very different from station to station, unless tight seismological prescriptions are enforced. However, that is not the point of using low-cost RS stations at individual homes, businesses, or schools. Our hope is that the redundancy of RS stations within a small footprint—a city—will suffice to ensure the availability of enough reliable data. This remains to be investigated in a quantitative manner as more stations come online.

    We noticed that reliability and continuity of service are an issue, even though we tried our best to place the RS instruments at locations with continuous power and reliable Internet. One RS station host wanted to negotiate communication costs and, after a few days, apparently disconnected his station. Another station, located in a power-secure part of Port-au-Prince that had not previously needed power backup, is now experiencing regular blackouts. This underscores the importance of observation redundancy, with many stations at short distances from each other, because one never knows which one will have an issue and stop operating when an interesting earthquake shows up.

    A Work in Progress

    We were positively impressed by the response of civil society members and the private sector to this initiative. However, to gain the support of civil society, it is clear that we need to provide RS hosts with personalized information, such as “your RS instrument detected an earthquake of magnitude 2.5 located 50 kilometers away, in the area of….” A smartphone application would be a great way to provide this information in quasi-real time and keep station hosts engaged. It could also serve to broadcast information on earthquake preparedness and hence use the (fortunately long!) time intervals between large earthquakes to educate and promote earthquake safety.

    With the lessons learned during this pilot experiment, our goal now is to push forward and engage the civil society and the private sectors—at least those entities that can afford continuous power and Internet—to be a bigger part of this project. Expanding the project would provide more RS stations and thus redundancy and continuity of service. It would also engage RS hosts in a project that puts them at the center of the information chain. RS hosts will become information providers to scientists rather than passive listeners to scarce and unintelligible information.

    It is our hope that as RS hosts and others become more aware of the earthquake issue, they will share information they will be privy to. We hope that they will become advocates for seismic monitoring, but more important, we hope that they will act to reduce seismic risk for themselves and their community.

    Acknowledgments

    This pilot activity is funded by the Interreg Caraibes/European Regional Development Fund (FEDER) program through the PREST (vers la Plateforme Régionale de Surveillance Tellurique du Futur) project, the Centre National de la Recherche Scientifique/French Institute for Research and Development (IRD) Risques Naturels program, and the Jeune Equipe Associée of the IRD. All data from the RS stations installed in Haiti are openly available via the Raspberry Shake International Federation of Digital Seismograph Networks (FDSN) web services. We thank Maurice Lamontagne and two anonymous reviewers for their constructive comments.

    References

    Anthony, R. E., et al. (2018), Do low‐cost seismographs perform well enough for your network? An overview of laboratory tests and field observations of the OSOP Raspberry Shake 4D, Seismol. Res. Lett., 90(1), 219–228, https://doi.org/10.1785/0220180251.

    Bent, A. L., et al. (2018), Real‐time seismic monitoring in Haiti and some applications, Seismol. Res. Lett., 89(2A), 407–415, https://doi.org/10.1785/0220170176.

    Cochran, E. S., et al. (2009), The Quake-Catcher Network: Citizen science expanding seismic horizons, Seismol. Res. Lett., 80(1), 26–30, https://doi.org/10.1785/gssrl.80.1.26.

    See the full article here .

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    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

    Earthquake Alert

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    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.

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    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

     
  • richardmitnick 8:16 am on April 22, 2019 Permalink | Reply
    Tags: , Earthquakes, Hydrophones, MERMAIDs, ,   

    From Science Magazine: “These ocean floats can hear earthquakes, revealing mysterious structures deep inside Earth” 

    AAAS
    From Science Magazine

    Apr. 17, 2019
    Erik Stokstad

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    A MERMAID undergoes testing off Japan’s coast in 2018. ALEX BURKY/PRINCETON UNIVERSITY

    A versatile, low-cost way to study Earth’s interior from sea has yielded its first images and is scaling up. By deploying hydrophones inside neutrally buoyant floats that drift through the deep ocean, seismologists are detecting earthquakes that occur below the sea floor and using the signals to peer inside Earth in places where data have been lacking.

    In February, researchers reported that nine of these floats near Ecuador’s Galápagos Islands had helped trace a mantle plume—a column of hot rock rising from deep below the islands. Now, 18 floats searching for plumes under Tahiti have also recorded earthquakes, the team reported last week at the European Geosciences Union (EGU) meeting here. “It seems they’ve made a lot of progress,” says Barbara Romanowicz, a geophysicist at the University of California, Berkeley.

    The South Pacific fleet will grow this summer, says Frederik Simons, a seismologist at Princeton University who helped develop the floats, called MERMAIDs (mobile earthquake recorders in marine areas by independent divers). He envisions a global flotilla of thousands of these wandering devices, which could also be used to detect the sound of rain or whales, or outfitted with other environmental or biological sensors. “The goal is to instrument all the oceans.”

    For decades, geologists have placed seismometers on land to study how powerful, faraway earthquakes pass through Earth. Deep structures of different density, such as the cold slabs of ocean crust that sink into the mantle along subduction zones, can speed up or slow down seismic waves. By combining seismic information detected in various locations, researchers can map those structures, much like 3D x-ray scans of the human body. Upwelling plumes and other giant structures under the oceans are more mysterious, however. The reason is simple: There are far fewer seismometers on the ocean floor.

    Such instruments are expensive because they must be deployed and retrieved by research vessels. And sometimes they fail to surface after yearlong campaigns. More recently, scientists have begun to use fiber optic communication cables on the sea floor to detect quakes, but the approach is in its infancy.

    MERMAIDs are a cheap alternative. They drift at a depth of about 1500 meters, which minimizes background noise and lessens the energy needed for periodic ascents to transmit fresh data. Whenever a MERMAID’s hydrophone picks up a strong sound pulse, its computer evaluates whether that pressure wave likely originated from seafloor shaking. If so, the MERMAID surfaces within a few hours and sends the seismogram via satellite.

    The nine floats released near the Galápagos in 2014 gathered 719 seismograms in 2 years before their batteries ran out. Background noise, such as wind and rain at the ocean surface, drowned out some of the seismograms. But 80% were helpful in imaging a mantle plume some 300 kilometers wide and 1900 kilometers deep, the team described in February in Scientific Reports. The widely dispersed MERMAIDs sharpened the picture, compared with studies done with seismometers on the islands and in South America. “The paper demonstrates the potential of the methodology, but I think they need to figure out how to beat down the noise a little more,” Romanowicz says.

    Since that campaign, the MERMAID design was reworked by research engineer Yann Hello of Geoazur, a geoscience lab in Sophia Antipolis, France. He made them spherical and stronger, and tripled battery life. The floats now cost about $40,000, plus about $50 per month to transmit data. “The MERMAIDs are filling a need for a fairly inexpensive, flexible device” to monitor the oceans, says Martin Mai, a geophysicist at King Abdullah University of Science and Technology in Thuwal, Saudi Arabia.

    Between June and September of 2018, 18 of these new MERMAIDs were scattered around Tahiti to explore the Pacific Superswell, an expanse of oddly elevated ocean crust, likely inflated by plumes. The plan is to illuminate this plumbing and find out whether multiple plumes stem from a single deep source. “It’s a pretty natural target,” says Catherine Rychert, a seismologist at the University of Southampton in the United Kingdom. “You’d need a lot of ocean bottom seismometers, a lot of ships, so having floats out there makes sense.”

    So far, the MERMAIDs have identified 258 earthquakes, Joel Simon, a graduate student at Princeton, told the EGU meeting. About 90% of those have also been detected by other seismometers around the world—an indication that the hydrophones are detecting informative earthquakes. Simon has also identified some shear waves, or S-waves, which arrive after the initial pressure waves of a quake and can provide clues to the mantle’s composition and temperature. “We never set out to get S-waves,” he said. “This is incredible.” S-waves can’t travel through water, so they are converted to pressure waves at the sea floor, which saps their energy and makes them hard to identify.

    In August, 28 more MERMAIDS will join the South Pacific fleet, two dozen of them bought by the Southern University of Science and Technology in Shenzhen, China. Heiner Igel, a geophysicist at Ludwig Maximilian University in Munich, Germany, cheers the expansion. “I would say drop them all over the oceans,” he says.

    See the full article here .


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  • richardmitnick 8:14 am on March 28, 2019 Permalink | Reply
    Tags: "Did the Moon trigger Saturday’s M=6.1 earthquake in Colombia?", , Earthquakes, , ,   

    From temblor: “Did the Moon trigger Saturday’s M=6.1 earthquake in Colombia?” 

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    From temblor

    March 27, 2019
    Aron Mirwald, M.Sc., Temblor, Inc.

    A magnitude 6.1 earthquake occurred on 23 March 2019 at 2:14 pm in Colombia. A recent scientific paper reports that the tide might be responsible for 16% of the earthquakes in Colombia. But did the Moon trigger this earthquake? Possibly, but there are important limitations.

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    Colombia’s hyperactive Cauca Cluster and Bucaramanga Nest

    The M=6.1 quake, which was widely felt in Bogota, Cali, and Medellin, was located in the well-known ‘Cauca cluster’ in Colombia, where M≥3 earthquakes occur frequently (~24 per year). Together with the ‘Bucaramanga nest’ (~550 per year), the two clusters account for over half of all Colombian earthquakes (Geological Service Colombia). Most of the earthquakes in the two clusters strike at depths between 70-180 km (43 -111 mi). How earthquakes can be produced at these great depths is itself an enigma, and a matter of ongoing research (read this and this for an introduction).

    But, as for many geoscience problems, there is more to it: Researchers from the Medellin University have found that earthquakes in Colombia correlate with the tide. They show in their recent publication that the relation between earthquakes and tide is especially strong for earthquakes within the two earthquake clusters (Monaco et. al., 2019).

    2
    Each dot represents an earthquake. The colored dots are corresponding to earthquakes in seismic clusters. The upper two are the Cauca cluster and Bucaramanga nest, where over half of the earthquakes in Colombia occur.

    The Moon and the Sun cause the Earth to deform

    Maybe you have heard that we are slightly lighter when the moon is above us (only one millionth of our weight). But, to be exact, this is also true if the moon is directly below us, at the opposite side. The reason for this is that the gravitational force is not the only force at play. The earth is moved by the moon circling around it, and we experience a centrifugal force because of this (here is a webpage with a great animation of this). The net force is upwards both at the side that faces the moon and at the opposite one.

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    Both Moon and Earth move in ellipses due to the force they exert on each other. The white arrows represent the net force, i.e. the sum of the centrifugal force and the gravitational force.
    Image from http://beltoforion.de (interactive animation)

    The moon is not the only one who influences the earth. The sun does it in a similar way, although the force it generates is about half as large. The combined effect of the Sun and the Moon is called ‘tide’. The tide has two effects on the earth. First, it moves large quantities of water, also known as ocean tide. Second, it deforms the solid earth: The tidal forces, that pull on both sides, elongate the planet, making it around 40 cm longer. This generates shear and unclamping stresses in the earth that can promote earthquakes (Heaton, 1975).

    The magnitudes of the stresses generated by the tide are much smaller than stresses due to the movement of the tectonic plates. This means that tides themselves are not responsible for earthquakes. Perhaps, however, if an earthquake is about to trigger, the tide can nudge it to fail. Therefore, we would expect seismicity to be higher when the tidal stresses and the tectonic stresses point in the same direction, and lower when the opposite is true.

    Searching for periodicity: can we prove tidal triggering?

    There are two key tidal cycles: The first one is 27.5 days long, which is the time the moon needs to circle around the earth. The second one is 24 hours long, which is the time the earth takes to turn around its own axis. If an increase in the rate of earthquakes correlates with these periods, then that increase could be tidally triggered. The next step would then be to actually compute the stresses involved.

    Could the tides permit earthquake forecasts?

    Since 1980 seismologists have searched for such a link, with mixed results. Recent studies, which have found a relation, are limited to certain regions or circumstances (Ide et. al., 2016). For example, it was found that the number of earthquakes in the region of the 2011 Tohoku earthquake in Japan was correlated with the tide before the earthquake occurred. After the magnitude 9 earthquake, on the other hand, no correlation was found (Tanaka et. al., 2012). Studies like this speculate that it might be possible to evaluate if a large rupture is about to come in certain areas, but this has yet to be proven.

    The recent event was probably facilitated by the tide

    In their research, Dr. Gloria Moncayo and her colleagues evaluated earthquakes in Colombia between 1993 and 2017. They found that the rate of earthquakes indeed had a periodic component, with a period of 27.5 days. About one-sixth (or 16%) more earthquakes occur when the moon is closest, i.e. at a full moon. This correlation between earthquakes and tides was strongest for the events within the Cauca cluster and the Bucaramanga nest.

    The recent earthquake occurred just three days after the last full moon (20 March). In the figure below, this corresponds to a phase of 34°, and thus in an area where more earthquakes are expected due to the tide. We contacted the authors of the research in order to learn more.

    Dr. Moncayo told us that the position and the timing of the event indicated tidal triggering. Her colleague, Dr. Jorge I. Zuluaga, added that they calculated the tidal stress for this event and found that its direction was such that the earthquake would be facilitated. ‘If I could bet a dollar, I would bet that it was tidally triggered. Regretfully, we cannot falsify this assertion’, he wrote.

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    Here, you see the number of earthquakes in relation to the 27.5-day period of the moon. A phase of 0 and 360 degrees corresponds to a full moon, and 180 degrees to a new moon. You can see that only a small fraction of the total number of earthquakes varies with time.
    Image from Moncayo et. al. (2019)

    Putting it into perspective: A tidal nudge, but not an earthquake prediction

    For last Saturday’s event, we know that the tidal stress favored the triggering. Before we jump into hasty conclusions, we should be aware that there are limitations to the result of the study of Dr. Moncayo and her colleagues. An important one is that the seismological network has expanded in the time they evaluated. This could introduce error in the detection of periodicity (Ader and Avouac, 2013). Even if the periodicity that the authors found was true, still most of the earthquakes are independent of the tide. Only a fraction (less than 16%) of the seismicity could be attributed to it. Finally, we need to know the actual tidal stresses and not only the periodicity to make statements of the causality.

    References

    Ader, T. J., & Avouac, J. P. (2013). Detecting periodicities and declustering in earthquake catalogs using the Schuster spectrum, application to Himalayan seismicity. Earth and Planetary Science Letters, 377, 97-105.

    Heaton, T. H. (1975). Tidal triggering of earthquakes. Geophysical Journal International, 43(2), 307-326.

    Ide, S., Yabe, S., & Tanaka, Y. (2016). Earthquake potential revealed by tidal influence on earthquake size–frequency statistics. Nature Geoscience, 9(11), 834.

    Moncayo, G. A., Zuluaga, J. I., & Monsalve, G. (2019). Correlation between tides and seismicity in Northwestern South America: the case of Colombia. Journal of South American Earth Sciences, 89, 227-245.

    Tanaka, S. (2012). Tidal triggering of earthquakes prior to the 2011 Tohoku‐Oki earthquake (Mw 9.1). Geophysical research letters, 39(7).

    https://www2.sgc.gov.co/sismos/sismos/ultimos-sismos.html

    http://beltoforion.de/article.php?a=tides_explained&hl=en&p=tides_applet&s=idPageTop#idPageTop

    http://temblor.net/earthquake-insights/the-riddle-of-the-19-september-2017-mexican-earthquake-8481/

    http://news.mit.edu/2013/study-faults-a-runaway-mechanism-in-intermediate-depth-earthquakes-1223

    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 1:46 am on March 16, 2019 Permalink | Reply
    Tags: Associate Professor Masaki Ando from the Department of Physics invented a novel kind of gravimeter — the torsion bar antenna (TOBA) — which aims to be the first of such instruments, , Earthquakes, Gravimeters — sensors which measure the strength of local gravity, , ,   

    From University of Tokyo: “Sensing shakes” 

    From University of Tokyo

    March 11, 2019

    A new way to sense earthquakes could help improve early warning systems.

    Earthquake Research Institute

    1
    Contour maps depict changes in gravity gradient immediately before the earthquake hits. The epicenter of the 2011 Tohoku earthquake is marked by (✩). ©2019 Kimura Masaya.

    Every year earthquakes worldwide claim hundreds or even thousands of lives. Forewarning allows people to head for safety and a matter of seconds could spell the difference between life and death. UTokyo researchers demonstrate a new earthquake detection method — their technique exploits subtle telltale gravitational signals traveling ahead of the tremors. Future research could boost early warning systems.

    The shock of the 2011 Tohoku earthquake in eastern Japan still resonates for many. It caused unimaginable devastation, but also generated vast amounts of seismic and other kinds of data. Years later researchers still mine this data to improve models and find novel ways to use it, which could help people in the future. A team of researchers from the University of Tokyo’s Earthquake Research Institute (ERI) found something in this data which could help the field of research and might someday even save lives.

    It all started when ERI Associate Professor Shingo Watada read an interesting physics paper on an unrelated topic by J. Harms from Istituto Nazionale di Fisica Nucleare in Italy. The paper suggests gravimeters — sensors which measure the strength of local gravity — could theoretically detect earthquakes.

    “This got me thinking,” said Watada. “If we have enough seismic and gravitational data from the time and place a big earthquake hit, we could learn to detect earthquakes with gravimeters as well as seismometers. This could be an important tool for future research of seismic phenomena.”

    The idea works like this. Earthquakes occur when a point along the edge of a tectonic plate comprising the earth’s surface makes a sudden movement. This generates seismic waves which radiate from that point at 6-8 kilometers per second. These waves transmit energy through the earth and rapidly alter the density of the subsurface material they pass through. Dense material imparts a slightly greater gravitational attraction than less dense material. As gravity propagates at light speed, sensitive gravimeters can pick up these changes in density ahead of the seismic waves’ arrival.

    2
    A map of Japan showing locations for the epicenter of the 2011 Tohoku earthquake (✩),Kamioka (K), Matsushiro (M) and seismic survey instruments used (△ and ●). ©2019 Kimura Masaya.

    “This is the first time anyone has shown definitive earthquake signals with such a method. Others have investigated the idea, yet not found reliable signals,” elaborated ERI postgraduate Masaya Kimura. “Our approach is unique as we examined a broader range of sensors active during the 2011 earthquake. And we used special processing methods to isolate quiet gravitational signals from the noisy data.”

    Japan is famously very seismically active so it’s no surprise there are extensive networks of seismic instruments on land and at sea in the region. The researchers used a range of seismic data from these and also superconducting gravimeters (SGs) in Kamioka, Gifu Prefecture, and Matsushiro, Nagano Prefecture, in central Japan.

    The signal analysis they performed was extremely reliable scoring what scientists term a 7-sigma accuracy, meaning there is only a one-in-a-trillion chance a result is incorrect. This fact greatly helps to prove the concept and will be useful in calibration of future instruments built specifically to help detect earthquakes. Associate Professor Masaki Ando from the Department of Physics invented a novel kind of gravimeter — the torsion bar antenna (TOBA) — which aims to be the first of such instruments.

    3
    A TOBA with door open to reveal cryogenically cooled sensor platform inside. ©2019 Ando Masaki.

    “SGs and seismometers are not ideal as the sensors within them move together with the instrument, which almost cancels subtle signals from earthquakes,” explained ERI Associate Professor Nobuki Kame. “This is known as an Einstein’s elevator, or the equivalence principle. However, the TOBA will overcome this problem. It senses changes in gravity gradient despite motion. It was originally designed to detect gravitational waves from the big bang, like earthquakes in space, but our purpose is more down-to-earth.”

    The team dreams of a network of TOBA distributed around seismically active regions, an early warning system that could alert people 10 seconds before the first ground shaking waves arrive from an epicenter 100 km away. Many earthquake deaths occur as people are caught off-guard inside buildings that collapse on them. Imagine the difference 10 seconds could make. This will take time but the researchers continually refine models to improve accuracy of the method for eventual use in the field.

    Science paper:
    “Earthquake-induced prompt gravity signals identified in dense array data in Japan,” Masaya Kimura; Nobuki Kame; Shingo Watada; Makiko Ohtani; Akito Araya; Yuichi Imanishi; Masaki Ando; Takashi Kunugi
    Earth, Planets and Space

    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 University of Tokyo aims to be a world-class platform for research and education, contributing to human knowledge in partnership with other leading global universities. The University of Tokyo aims to nurture global leaders with a strong sense of public responsibility and a pioneering spirit, possessing both deep specialism and broad knowledge. The University of Tokyo aims to expand the boundaries of human knowledge in partnership with society. Details about how the University is carrying out this mission can be found in the University of Tokyo Charter and the Action Plans.

     
  • richardmitnick 9:58 am on February 26, 2019 Permalink | Reply
    Tags: "Seismic warning to India: A shock strikes just north of Delhi", , , , Earthquakes, , , ,   

    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 12:38 pm on February 13, 2019 Permalink | Reply
    Tags: , Earthquakes, Indonesia’s devastating 2018 earthquake was a rare ‘supershear’ according to UCLA-led study, , ,   

    From UCLA Newsroom: “Indonesia’s devastating 2018 earthquake was a rare ‘supershear,’ according to UCLA-led study” 


    From UCLA Newsroom

    February 11, 2019

    Stuart Wolpert
    310-206-0511
    swolpert@stratcomm.ucla.edu

    1
    Pierre Prakash/European Union

    In supershear quakes, the rupture moves faster than the shear waves, which produces more energy in a shorter time, making supershears unusually destructive.

    The devastating 7.5 magnitude earthquake that struck the Indonesian island of Sulawesi last September was a rare “supershear” earthquake, according to a study led by UCLA researchers.

    Only a dozen supershear quakes have been identified in the past two decades, according to Lingsen Meng, UCLA’s Leon and Joanne V.C. Knopoff Professor of Physics and Geophysics and one of the report’s senior authors. The new study was published Feb. 4 in the journal Nature Geoscience.

    Meng and a team of scientists from UCLA, France’s Geoazur Laboratory, the Jet Propulsion Laboratory at Caltech, and the Seismological Laboratory at Caltech analyzed the speed, timing and extent of the Palu earthquake. Using high-resolution observations of the seismic waves caused by the temblor, along with satellite radar and optical images, they found that the earthquake propagated unusually fast, which identified it as a supershear.

    Supershear earthquakes are characterized by the rupture in the earth’s crust moving very fast along a fault, causing the up-and-down or side-to-side waves that shake the ground — called seismic shear waves — to intensify. Shear waves are created in standard earthquakes, too, but in supershear quakes, the rupture moving faster than the shear waves produces more energy in a shorter time, which is what makes supershears even more destructive.

    “That intense shaking was responsible for the widespread landslides and liquefactions [the softening of soil caused by the shaking, which often causes buildings to sink into the mud] that followed the Palu earthquake,” Meng said.

    In fact, he said, the vibrations produced by the shaking of supershear earthquakes is analogous to the sound vibrations of the sonic boom produced by supersonic jets.

    2
    Lingsen Meng. Penny Jennings/UCLA

    UCLA graduate student Han Bao, the report’s first author, gathered publicly available ground-motion recordings from a sensor network in Australia — about 2,500 miles away from where the earthquake was centered — and used a UCLA-developed source imaging technique that tracks the growth of large earthquakes to determine its rupture speed. The technique is similar to how a smartphone user’s location can be determined by triangulating the times that phone signals arrive at cellphone antenna towers.

    “Our technique uses a similar idea,” Meng said. “We measured the delays between different seismic sensors that record the seismic motions at set locations.”

    The researchers could then use that to determine the location of the rupture at different times during the earthquake.

    They determined that the minute-long quake moved away from the epicenter at 4.1 kilometers per second (or about 2.6 miles per second), faster than the surrounding shear-wave speed of 3.6 kilometers per second (2.3 miles per second). By comparison, non-shear earthquakes more at about 60 percent of that speed — around 2.2 kilometers per second (1.3 miles per second), Meng said.

    Previous supershear earthquakes — like the magnitude 7.8 Kunlun earthquake in Tibet in 2001 and the magnitude 7.9 Denali earthquake in Alaska in 2002 — have occurred on faults that were remarkably straight, meaning that there were few obstacles to the quakes’ paths. But the researchers found on satellite images of the Palu quake that the fault line had two large bends. The temblor was so strong that the rupture was able to maintain a steady speed around these bends.

    That could be an important lesson for seismologists and other scientists who assess earthquake hazards.

    “If supershear earthquakes occur on nonplanar faults, as the Palu earthquake did, we have to consider the possibility of stronger shaking along California’s San Andreas fault, which has many bends, kinks and branches,” Meng said.

    Supershear earthquakes typically start at sub-shear speed and then speed up as they continue. But Meng said the Palu earthquake progressed at supershear speed almost from its inception, which would imply that there was high stress in the rocks surrounding the fault — and therefore stronger shaking and more land movement in a compressed amount of time than would in standard earthquakes.

    “Geometrically irregular rock fragments along the fault plane usually act as barriers preventing earthquakes,” Meng said. “However, if the pressure accumulates for a long time — for decades or even hundreds of years — an earthquake will eventually overcome the barriers and will go supershear right away.”

    Among the paper’s other authors are Tian Feng, a UCLA graduate student, and Hui Huang, a UCLA postdoctoral scholar. The UCLA researchers were supported by the National Science Foundation and the Leon and Joanne V.C. Knopoff Foundation.

    The other authors are Cunren Liang of the Seismological Laboratory at Caltech; Eric Fielding and Christopher Milliner of JPL at Caltech and Jean-Paul Ampuero of Geoazur.


    See the full article here .


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

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

    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

     
  • richardmitnick 11:52 am on January 24, 2019 Permalink | Reply
    Tags: , Earthquakes, Peru-Chile Trench, , , 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

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

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

    1

    From temblor

    January 16, 2019
    Jason Patton, Ph.D.

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

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

    What if the Northridge Earthquake Happened Today?

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

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

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

    What about other quakes in the Southland?

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

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

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

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

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

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

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

    The partial shutdown could make things worse

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

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

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

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

    3

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

    Seismic swarms are simply unchartered shutdown territory.

    Rate of Insurance Coverage is Down

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

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

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

    Out of sight, out of mind

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

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

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

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

    References

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

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

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

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

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

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

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

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

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

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

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

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

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

    Get the app in the Google Play store.

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

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    The primary project partners include:

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

    The Earthquake Threat

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

    Part of the Solution

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

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

    System Goal

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

    Current Status

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

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

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

    Authorities

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

    For More Information

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

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

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

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

    1

    From temblor

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    References

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

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

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

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

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

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Earthquake Alert

    1

    Earthquake Alert

    Earthquake Network project

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

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

    Get the app in the Google Play store.

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

    Meet The Quake-Catcher Network

    QCN bloc

    Quake-Catcher Network

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    The primary project partners include:

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

    The Earthquake Threat

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

    Part of the Solution

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

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

    System Goal

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

    Current Status

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

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

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

    Authorities

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

    For More Information

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

    Learn more about EEW Research

    ShakeAlert Fact Sheet

    ShakeAlert Implementation Plan

     
  • richardmitnick 10:54 am on November 8, 2018 Permalink | Reply
    Tags: , “It’s not just about engineering a stronger building. Rather it’s about designing a more resilient city by reducing damage and overcoming impeding factors that can interfere with recovery.”, Earthquakes, , How will San Francisco’s skyscrapers fare after the next Big One?, If one or more high-rises suffers serious damage how badly could that disrupt the rest of the city?, Survey reveals that many high-rises built before 1990 were constructed with a type of steel frame that developed dangerous cracks in the welds during the 1994 Northridge earthquake in Los Angeles   

    From Stanford University Engineering: “How will San Francisco’s skyscrapers fare after the next Big One?” 

    Stanford University Name
    From Stanford University Engineering

    November 06, 2018
    Edmund L. Andrews

    1
    It’s not just about engineering a stronger building. It’s about designing a more resilient city. | Unsplash/Hardik Pandya

    When Greg Deierlein looks at San Francisco’s skyline, he wonders: Will the city be ready if a major earthquake shakes those skyscrapers?

    It’s not primarily a question of whether all the towers will remain standing, though there are some concerns about the ones built more than 30 years ago. The more complicated question is this, says Deierlein, the John A. Blume Professor in the School of Engineering: If one or more high-rises suffers serious damage, how badly could that disrupt the rest of the city?

    “Traditionally, the building codes for seismic design have focused on collapse safety and preventing the loss of life,” he says. “A full reckoning should also take into account the potential costs during the recovery.” For instance, a single damaged high-rise apartment building could force hundreds of residents out of their homes for months — bad news for a city that’s already notoriously short on housing. Likewise, an office tower that becomes temporarily unusable could cost the city millions of dollars in lost economic activity. And should a damaged skyscraper be at risk of collapsing, it would pose a danger to everything in its shadow. “What,” Deierlein asks, “would be the cumulative effects of this disruption on the health and welfare of the city?”

    The city of San Francisco wants to know, too. In recent years city officials have been developing a sweeping new strategy on earthquake preparedness for skyscrapers, the first such effort by a city in the United States, and Deierlein and his team have been providing city leaders with hard data and new modeling tools to better estimate the costs associated with disruption and downtime.

    As a start, he and his colleagues, including Stanford PhD candidates Anne Hulsey and Wen-Yi Yen, inventoried 156 San Francisco buildings that rise 240 feet or more, noting their age, design and potential weaknesses. Their survey reveals that many high-rises built before 1990 were constructed with a type of steel frame that developed dangerous cracks in the welds during the 1994 Northridge earthquake in Los Angeles. Research by Hulsey and Yen aims to assess the risks posed to these pre-Northridge buildings and the surrounding neighborhoods. Retrofitting these older buildings would be enormously expensive, Deierlein says. Complicated, too.

    ___________________________________________
    At the moment, owners are not required to complete new earthquake assessments, much less retrofits, unless they’re renovating at least two-thirds of a building. Most building owners carefully avoid hitting that trigger.
    ___________________________________________

    Partly as a result of the building inventory, city officials have recommended changing the triggers that require property owners to reassess their seismic risks and requiring that future reassessments factor in building recovery time as well as safety.

    San Francisco officials are also considering a number of recommendations for new buildings aimed at reducing downtime. These may include imposing tighter “drift limits” on the how much a building is permitted to sway in an earthquake, thereby reducing building damage and downtime. Another idea is to demand greater robustness in the building’s mechanical systems, from elevators and electrical systems to plumbing, which could reduce the time that all or part of a building is effectively unusable. They also propose requiring tall building owners to have a recovery plan that could include making advanced arrangements with engineers and contractors to repair damage after a quake.

    One major obstacle is the status of the city’s current high-rise housing stock. San Francisco’s official goal is to make sure that 95% of the city’s high-rise housing can be restored to habitability within a few weeks after an earthquake. But studies by the Stanford team indicate that a damaged high-rise condominium could be uninhabitable for two to six months. Although the repairs themselves might indeed take only a few weeks, it could take several additional months to make a full damage assessment, get the proper permits and enlist the engineers and contractors.

    The Stanford researchers also highlighted the possibility that a badly damaged skyscraper might force a city to cordon off all the streets and buildings in its shadow. In Christchurch, New Zealand, the central business district was shut down for more than two years after a 2011 earthquake. The San Francisco strategy calls for new protocols on setting up cordons, which are likely to be based in part on a model the Stanford team has developed to predict the risks.

    The underlying theme of all this work, Deierlein says, is to look at skyscrapers as more than individual buildings. “It’s all about interconnectedness,” he says. “It’s not just about engineering a stronger building. Rather, it’s about designing a more resilient city by reducing damage and overcoming impeding factors that can interfere with recovery.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Stanford University

    Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

    Stanford University Seal

     
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