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  • richardmitnick 8:49 pm on November 10, 2021 Permalink | Reply
    Tags: "Newly identified fault in Seal Beach. CA. quietly rattles beneath the city", , , Earthquake science, ,   

    From temblor : “Newly identified fault in Seal Beach. CA. quietly rattles beneath the city” 

    1

    From temblor

    November 8, 2021
    Dan Gish
    Steve Boljen

    The Los Angeles basin is home to countless faults that range from thousands of feet to hundreds of miles in length. These include normal faults, reverse faults, thrust faults and strike-slip faults. The Newport-Inglewood Fault Zone (NIFZ) — a series of faults that extends between Newport and Inglewood, California — is one of the major sources of seismicity in the area. Many experts believed this zone is associated with several notable earthquakes, particularly in the Long Beach-Seal Beach area, including the 1933 magnitude-6.4 Long Beach earthquake.

    Less widely known are the basin’s numerous near-surface faults, some of which were recently identified in the immediate Seal Beach area. Scientists at 3D Seismic Solutions, a seismic data consulting company, in partnership with researchers at The California Institute of Technology (US), recently discovered one particularly active fault in this area. The finding highlights the difficulty faced by emergency managers, city planners and engineers in knowing potential hazards when planning for future earthquakes.

    Identifying near-surface faults

    A high-density seismic survey of the subsurface was conducted in early 2017 over approximately 28 square miles (72 square kilometers) of Long Beach and Seal Beach. A total of 5,354 sensors continuously recorded ground movement in the area for eight weeks.

    At one point during this period, vibrator trucks were deployed to generate seismic waves within the survey area. These waves reflect off features below ground — such as faults — and are detected by the sensors at the surface. The energy these vibrator trucks put into the ground is benign and undetectable by humans at the surface, but akin to an MRI, the bouncing waves allow us to generate a three-dimensional image of the subsurface down to 14,000 feet below sea level.

    1
    Area covered by the 2017 high-density seismic hazard survey. Credit: 3D Seismic Solutions.

    The subsurface data revealed several faults that had not been previously identified. These shallow faults extend upward to within 300 feet (90 meters) of the surface, however human activity has obscured meaningful fault information higher up. Our observations in the area suggest that these faults have also deformed sediments near the surface relatively recently, indicating these areas, shown in red on the map below, may be subject to continued deformation. Although it is impossible to predict when or how likely these faults are to move in the future, these data suggest they are active.

    3
    Location of the newly identified shallow faults (purple), areas of recent deformation (red) and the current surface trace of the NIFZ (yellow).

    Thousands of tiny earthquakes

    In addition to the bouncing seismic waves from the vibrating trucks, the sensors detected more than 3,000 micro-earthquakes during the eight-week period. Micro-seismic events are small earthquakes that are imperceptible by people, even those who are standing directly on the epicenter.

    Seismic sensors record these tiny events that occur along faults when they slip or creep. These micro-earthquakes do not pose a danger and can even help scientists locate otherwise hidden faults.

    Researchers at Caltech plotted the epicenters of the micro-seismic events onto our map and found that many of the events struck in a cluster along a section of the coast, close to one of our newly mapped faults. The micro-earthquakes occurred between tens of feet to more than one mile (several meters to two kilometers) below the surface, which is consistent with the inferred depth of this fault. The strong correlation between the events and the fault location indicates the fault was active during the eight-week period the sensors were deployed.

    If the events were related to human activities, such as construction or drilling, they would likely be dispersed throughout the urban area. Alternatively, if they were seismic noise related to waves crashing on the beach, we would expect them to be present along the entire shoreline. Yet, the linear cluster does not extend north of the San Gabriel River; it abruptly ends at a point where the newly mapped fault bends inland.

    4
    Correlation of Caltech’s micro-seismic events with 3D Seismic Solution’s fault map. Newly mapped faults in purple, Newport-Inglewood fault trace in red, and black dots represent the micro-seismic events, which occurred down to more than one mile (two kilometers) below the surface.

    Seismic hazard from unknown faults

    The Alquist-Priolo Act was created following the 1971 magnitude-6.6 San Fernando Valley earthquake, which cause widespread damage to structures when the Sierra Madre Fault slipped at the surface. The intent of the act was to reduce earthquake loses by regulating development near active surface faults. However, as demonstrated by the 1933 Long Beach earthquake, and more recently by the magnitude-6.7 Northridge earthquake, severe damage can occur even when a fault does not rupture all the way to the surface.

    Some of the major challenges in assessing seismic hazard include identifying subsurface faults and knowing how the fault will move. Faults that are not easily observed in a landscape, either because they do not reach the surface or evidence of offset has been paved over or otherwise removed, can be difficult to identify without detailed study of the subsurface. Such faults can still pose a hazard and do occasionally slip in a major earthquake, surprising seismologists. The damaging Northridge earthquake itself occurred on a previously unknown thrust fault, highlighting the hazard hidden faults pose in the region.

    Understanding the complex structure of the subsurface and the location of the many faults is critical in assessing potential earthquake risks. Presently in the Seal Beach area, the only identified Alquist-Priolo zone is along the Newport-Inglewood fault. The seismic data shows there are additional near-surface faults, some of which are currently active. High-density seismic surveys give scientists, city planners and emergency managers a better understanding of the hazards present in the Los Angeles basin. Emergency planners are keenly interested in the location of faults that cross planned evacuation routes, as well as first responder and key infrastructure locations.

    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

    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

    QuakeAlertUSA

    1

    About Early Warning Labs, LLC

    Early Warning Labs, LLC (EWL) is an Earthquake Early Warning technology developer and integrator located in Santa Monica, CA. EWL is partnered with industry leading GIS provider ESRI, Inc. and is collaborating with the US Government and university partners.

    EWL is investing millions of dollars over the next 36 months to complete the final integration and delivery of Earthquake Early Warning to individual consumers, government entities, and commercial users.

    EWL’s mission is to improve, expand, and lower the costs of the existing earthquake early warning systems.

    EWL is developing a robust cloud server environment to handle low-cost mass distribution of these warnings. In addition, Early Warning Labs is researching and developing automated response standards and systems that allow public and private users to take pre-defined automated actions to protect lives and assets.

    EWL has an existing beta R&D test system installed at one of the largest studios in Southern California. The goal of this system is to stress test EWL’s hardware, software, and alert signals while improving latency and reliability.

    Earthquake Early Warning Introduction

    The United States Geological Survey (USGS), in collaboration with state agencies, university partners, and private industry, is developing an earthquake early warning system (EEW) for the West Coast of the United States called ShakeAlert. The USGS Earthquake Hazards Program aims to mitigate earthquake losses in the United States. Citizens, first responders, and engineers rely on the USGS for accurate and timely information about where earthquakes occur, the ground shaking intensity in different locations, and the likelihood is of future significant ground shaking.

    The ShakeAlert Earthquake Early Warning System recently entered its first phase of operations. The USGS working in partnership with the California Governor’s Office of Emergency Services (Cal OES) is now allowing for the testing of public alerting via apps, Wireless Emergency Alerts, and by other means throughout California.

    ShakeAlert partners in Oregon and Washington are working with the USGS to test public alerting in those states sometime in 2020.

    ShakeAlert has demonstrated the feasibility of earthquake early warning, from event detection to producing USGS issued ShakeAlerts ® and will continue to undergo testing and will improve over time. In particular, robust and reliable alert delivery pathways for automated actions are currently being developed and implemented by private industry partners for use in California, Oregon, and Washington.

    Earthquake Early Warning Background

    The objective of an earthquake early warning system is to rapidly detect the initiation of an earthquake, estimate the level of ground shaking intensity to be expected, and issue a warning before significant ground shaking starts. A network of seismic sensors detects the first energy to radiate from an earthquake, the P-wave energy, and the location and the magnitude of the earthquake is rapidly determined. Then, the anticipated ground shaking across the region to be affected is estimated. The system can provide warning before the S-wave arrives, which brings the strong shaking that usually causes most of the damage. Warnings will be distributed to local and state public emergency response officials, critical infrastructure, private businesses, and the public. EEW systems have been successfully implemented in Japan, Taiwan, Mexico, and other nations with varying degrees of sophistication and coverage.

    Earthquake early warning can provide enough time to:

    Instruct students and employees to take a protective action such as Drop, Cover, and Hold On
    Initiate mass notification procedures
    Open fire-house doors and notify local first responders
    Slow and stop trains and taxiing planes
    Install measures to prevent/limit additional cars from going on bridges, entering tunnels, and being on freeway overpasses before the shaking starts
    Move people away from dangerous machines or chemicals in work environments
    Shut down gas lines, water treatment plants, or nuclear reactors
    Automatically shut down and isolate industrial systems

    However, earthquake warning notifications must be transmitted without requiring human review and response action must be automated, as the total warning times are short depending on geographic distance and varying soil densities from the epicenter.

     
  • richardmitnick 10:36 am on November 9, 2021 Permalink | Reply
    Tags: "Unearthing the Cause of Slow Seismic Waves in Subduction Zones", , CMS: Condrey Mountain Schist, , Earthquake science, , , LVZs: low-velocity zones, Researchers look to the fossil rock record to unearth the driving forces for variable seismic speed through subduction zones., The orientation of minerals within the rocks can affect seismic velocities., The researchers conclude that LVZs in subduction zones mark where deformation between tectonic plates is occurring.   

    From Eos: “Unearthing the Cause of Slow Seismic Waves in Subduction Zones” 

    From AGU
    Eos news bloc

    From Eos

    9 November 2021
    Sarah Derouin

    Researchers look to the fossil rock record to unearth the driving forces for variable seismic speed through subduction zones.

    1
    Metamorphic rocks, like those pictured here, are commonly found in subduction zones. Researchers found that among other factors, the orientation of minerals within the rocks can affect seismic velocities. Credit: C. M. Tewksbury-Christle.

    In modern subduction zones—regions around the world that have one tectonic plate sliding past another—one area can act like molasses for seismic waves. These anomalous areas are called low-velocity zones, or LVZs. In these zones, seismic waves are up to 3 times slower than waves that whiz through the surrounding rock. Some scientists suggest that the slowdown is because the downgoing plate maintains an undeformed top layer, whereas other researchers propose that intense deformation between the two huge plates causes LVZs.

    In a new study, Tewksbury-Christle and Behr [Geophysical Research Letters] attempted to unearth the causes of LVZs. While prior work has tended to rely on seismic wave investigation on rocks 25–50 kilometers deep, the team decided to study something accessible by car. They examined a fossil subduction zone in Northern California from the Late Jurassic to the Early Cretaceous that has since returned to the surface. The rocks are called the Condrey Mountain Schist (CMS), a metamorphic rock (greenschist/epidote-amphibolite to epidote-blueschist) that is also expected at depth in modern subduction zones.

    The team tested the seismic velocity of the CMS in relation to the differences they observed in the subduction zone. They focused on the estimated width of the shear zone, the types of rocks within it, and the styles of deformation recorded by the rocks to determine what might affect the velocity in LVZs.

    They found that the LVZ in the fossil subduction zone was about 3 kilometers wide—similar to modern subduction LVZs that range from 3 to 8 kilometers wide. They also looked at mineral orientation, or fabric, in the metasedimentary rock and found that the direction and alignment of the minerals can affect seismic velocity. Last, the porosity of fractured zones also contributed to the LVZ within the subducted rock.

    The researchers conclude that LVZs in subduction zones mark where deformation between tectonic plates is occurring. They note that this study can help researchers better understand how plates move in subduction zones around the world.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    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.

     
  • richardmitnick 9:19 am on November 5, 2021 Permalink | Reply
    Tags: "Keeping one step ahead of earthquakes", , Earthquake science, , , ,   

    From Horizon The EU Research and Innovation Magazine : “Keeping one step ahead of earthquakes” 

    From Horizon The EU Research and Innovation Magazine

    03 November 2021
    Nick Klenske

    1
    As technologies continue to improve, earthquake-prone cities will be better prepared. © Marco Iacobucci Epp, Shutterstock.

    While accurately predicting earthquakes is in the realm of science fiction, early warning systems are very much a reality. As advances in research and technology make these systems increasingly effective, they’re vital to reducing an earthquake’s human, social and economic toll.

    Damaging earthquakes can strike at any time. While we can’t prevent them from occurring, we can make sure casualties, economic loss and disruption of essential services are kept to a minimum.

    Building more resilient cities is key to withstanding earthquake disasters. If we had a better idea of when earthquakes would strike, authorities could initiate local emergency, evacuation and shelter plans. But unfortunately, this is not the case.

    ‘Because earthquakes occur on faults, we know where they will occur. The problem is that we don’t know how to predict when an earthquake will strike,’’ explained Quentin Bletery, from the Research Institute for Development (IRD) in France. He is a researcher at the Géoazur laboratory at The University of Côte d’Azur [Université Côte d’Azur](FR).

    ‘Successful earthquake prediction must provide the location, time and magnitude of a future event with high accuracy, [something] which as of now, can’t be done,’ added Johannes Schweitzer, Principal Research Geophysicist at NORSAR, an independent research foundation specialised in seismology and seismic monitoring.

    Potential of AI to improve the accuracy and speed of early warning systems

    Earthquake early warning (EEW) systems are evolving rapidly thanks to advances in computer power and network communication.

    EEW systems work by identifying the first signals generated by an earthquake rupture before the strongest shaking and tsunami reach populated areas. These signals follow the origin of the earthquake and can be recorded seconds before the seismic waves.

    A promising, recently identified early signal is the prompt elasto-gravity signal (PEGS), which travels at the speed of light but is a million times smaller than seismic waves, and therefore, often goes undetected.

    According to Bletery, artificial intelligence (AI) could play a key role in identifying this signal. With the support of the EARLI project, he is leading an effort to develop an AI algorithm capable of doing exactly that.

    “Our AI system aims to increase the accuracy and speed of early warning systems by enabling them to pick up an extremely weak signal that precedes even the fastest seismic waves,” said Bletery.

    Albeit still in its very early stages, if the project succeeds, Bletery says public authorities will have access to nearly instantaneous information about an earthquake’s magnitude and location. “This would allow them to take such immediate mitigation efforts as, for example, shutting down infrastructure like trains and nuclear power plants and moving people to earthquake- and tsunami-safe zones,” he noted.

    Statistical technique to enhance seismic resilience

    Another approach to improve seismic seismic resilience and reduce human losses is operational earthquake forecasting (OEF). TURNkey, led by NORSAR, aims to improve the effectiveness of this statistical technique used to study seismic sequences to provide timely warnings.

    “OEF can inform us about changing seismic hazards over time, enabling emergency managers and public authorities to prepare for a potentially damaging earthquake,” explained Ivan Van Bever, TURNkey project manager. “What OEF can’t do, is provide warnings with a high level of accuracy.”

    In addition to improving existing methods, TURNkey is developing the “Forecasting – Early Warning – Consequence Prediction – Response” (FWCR) platform to increase the accuracy of earthquake warnings and ensure that all warning-related information is sent to end-users in a format that is both understandable and useful.

    “The platform will forecast and issue warnings for aftershocks and will improve the ability for users to estimate both direct and indirect losses,” said Van Bever

    Better prepared than ever

    The platform is currently being tested at six locations across Europe: Bucharest (Romania), the Pyrenees mountain range (France), the towns of Hveragerdi and Husavik (Iceland), the cities of Patras and Aigio (Greece), and the port of Gioia Tauro (Southern Italy). It is also being tested in Groningen province (Netherlands), which is affected by induced seismicity – minor earthquakes and tremors caused by human activity that alters the stresses and strains on the Earth’s crust.

    Johannes Schweitzer, who is the project coordinator, is confident the multi-sensor-based earthquake information system will prove capable of enabling early warning and rapid response. “The TURNkey platform will close the gap between theoretical systems and their practical application in Europe,” remarked Schweitzer. “In doing so, it will improve a city’s seismic resilience before, during and after a damaging earthquake.”

    “As these technologies and systems continue to improve, they could reduce an earthquake’s human, social and economic toll,” added Bletery.

    Earthquake-prone cities will be better prepared than ever before. At the very least these new systems will give people a heads up to drop, cover and hold on during an earthquake.

    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 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 University (US), and a year at California Institute of Technology (US), the QCN project is moving to the University of Southern California (US) 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

    QuakeAlertUSA

    1

    About Early Warning Labs, LLC

    Early Warning Labs, LLC (EWL) is an Earthquake Early Warning technology developer and integrator located in Santa Monica, CA. EWL is partnered with industry leading GIS provider ESRI, Inc. and is collaborating with the US Government and university partners.

    EWL is investing millions of dollars over the next 36 months to complete the final integration and delivery of Earthquake Early Warning to individual consumers, government entities, and commercial users.

    EWL’s mission is to improve, expand, and lower the costs of the existing earthquake early warning systems.

    EWL is developing a robust cloud server environment to handle low-cost mass distribution of these warnings. In addition, Early Warning Labs is researching and developing automated response standards
    and systems that allow public and private users to take pre-defined automated actions to protect lives and assets.

    EWL has an existing beta R&D test system installed at one of the largest studios in Southern California. The goal of this system is to stress test EWL’s hardware, software, and alert signals while improving latency and reliability.

    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

    Earthquake Early Warning Introduction

    The United States Geological Survey (USGS), in collaboration with state agencies, university partners, and private industry, is developing an earthquake early warning system (EEW) for the West Coast of the United States called ShakeAlert. The USGS Earthquake Hazards Program aims to mitigate earthquake losses in the United States. Citizens, first responders, and engineers rely on the USGS for accurate and timely information about where earthquakes occur, the ground shaking intensity in different locations, and the likelihood is of future significant ground shaking.

    The ShakeAlert Earthquake Early Warning System recently entered its first phase of operations. The USGS working in partnership with the California Governor’s Office of Emergency Services (Cal OES) is now allowing for the testing of public alerting via apps, Wireless Emergency Alerts, and by other means throughout California.

    ShakeAlert partners in Oregon and Washington are working with the USGS to test public alerting in those states sometime in 2020.

    ShakeAlert has demonstrated the feasibility of earthquake early warning, from event detection to producing USGS issued ShakeAlerts ® and will continue to undergo testing and will improve over time. In particular, robust and reliable alert delivery pathways for automated actions are currently being developed and implemented by private industry partners for use in California, Oregon, and Washington.

    Earthquake Early Warning Background

    The objective of an earthquake early warning system is to rapidly detect the initiation of an earthquake, estimate the level of ground shaking intensity to be expected, and issue a warning before significant ground shaking starts. A network of seismic sensors detects the first energy to radiate from an earthquake, the P-wave energy, and the location and the magnitude of the earthquake is rapidly determined. Then, the anticipated ground shaking across the region to be affected is estimated. The system can provide warning before the S-wave arrives, which brings the strong shaking that usually causes most of the damage. Warnings will be distributed to local and state public emergency response officials, critical infrastructure, private businesses, and the public. EEW systems have been successfully implemented in Japan, Taiwan, Mexico, and other nations with varying degrees of sophistication and coverage.

    Earthquake early warning can provide enough time to:
    Instruct students and employees to take a protective action such as Drop, Cover, and Hold On
    Initiate mass notification procedures
    Open fire-house doors and notify local first responders
    Slow and stop trains and taxiing planes
    Install measures to prevent/limit additional cars from going on bridges, entering tunnels, and being on freeway overpasses before the shaking starts
    Move people away from dangerous machines or chemicals in work environments
    Shut down gas lines, water treatment plants, or nuclear reactors
    Automatically shut down and isolate industrial systems

    However, earthquake warning notifications must be transmitted without requiring human review and response action must be automated, as the total warning times are short depending on geographic distance and varying soil densities from the epicenter.

    GNSS-Global Navigational Satellite System

    1
    GNSS station | Pacific Northwest Geodetic Array, Central Washington University (US)
    _____________________________________________________________________________________

     
  • richardmitnick 7:50 pm on October 21, 2021 Permalink | Reply
    Tags: "Caribbean-South American plate boundary primed for major earthquake", Earthquake science,   

    From Pennsylvania State University (US) : “Caribbean-South American plate boundary primed for major earthquake” 

    Penn State Bloc

    From Pennsylvania State University (US)

    October 20, 2021
    Matthew Carroll

    1
    Laboratoire de Géologie de l’ENS
    Bienvenue au Laboratoire de Géologie de l’École normale supérieure de Paris

    Faults along the central portion of the Caribbean-South American tectonic plate boundary are primed to produce a powerful earthquake, posing a potentially serious hazard to northern Venezuela, according to an international team of scientists.

    “Most of the populated cities in this region happen to be on a plate boundary, so it’s important to understand the seismic hazard,” said Machel Higgins, who led the research as part of his doctorate at Penn State. “We found a significant portion of the Caribbean-South American plate boundary is locked and capable of producing up to a magnitude 8 earthquake.”

    The boundary is a roughly 550-mile stretch where two tectonic plates slide past each other from northern Venezuela and the Caribbean Sea in the west to Trinidad and Tobago in the east. Multiple faults extend along the boundary, and the region is prone to earthquakes.

    “There have been many destructive earthquakes on this plate, particularly magnitude 7 and above around Venezuela’s capital, Caracas, in 1812 and 1900,” said Higgins, who graduated in spring 2021. “The elastic strain buildup we’ve calculated here could produce a similarly large earthquake that has seismic hazard implications for Caracas and surrounding urban areas in northern Venezuela.”

    The team, led by Penn State scientists, combined GPS and Interferometric Synthetic Aperture Radar (InSAR) data to observe small changes to the ground along the boundary and used that to model where strain is building along the faults, indicating where the potential for earthquakes exists.

    “This is the first time this segment of the Caribbean – South American plate boundary has been investigated completely, and our results show where significant strain is accumulating,” said Peter LaFemina, professor of geosciences and Higgin’s adviser.

    Faults on the eastern end of the boundary, with one exception, are creeping, which means the plates are sliding past each other smoothly. The western faults are locked, which means they are hung up and unable to move. When this happens, stress builds up until the plates release, triggering an earthquake, the scientists said.

    “That strain is typically relieved by rupturing during an earthquake or freely slipping, which is called creeping,” Higgins said. “We’ve found that where there have been large historical earthquakes there is a high magnitude of elastic strain build up. And where there have been many small magnitude earthquakes or few earthquakes, there was virtually no elastic strain buildup.”

    The Caribbean plate moves about 20 millimeters a year to the east relative to the South American plate, and the researchers found a single slipping fault on the island of Trinidad is responsible for accommodating 70% of the relative motion.

    “We knew the Central Range Fault in Trinidad was creeping and accommodating roughly 70% of the relative plate motion; however, our new results show that the fault is creeping across the entire island,” LaFemina said.

    This is the first study to combine GPS and InSAR techniques to study the entire length of the plate boundary. The results, recently published in the journal Tectonics [no reference or link], could help guide future seismic hazard decisions in northern Venezuela and Trinidad and Tobago, the scientists said.

    “It’s very difficult to assess the dangers of a magnitude 8 earthquake; they include not only loss of life, but downstream economic damages,” Higgins said. “Because this area is somewhat dependent on the production of petroleum, a large earthquake that damages that infrastructure could set their economies back.”

    Christelle Wauthier, associate professor of geosciences at Penn State, also participated in this research.

    John C. Weber, professor of geology at Grand Valley State University (US); Halldór Geirsson, associate professor at The University of Iceland(IS); and Graham Ryan, director of the Montserrat Volcano Observatory(MS), also contributed.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Penn State Campus

    The Pennsylvania State University (US) is a public state-related land-grant research university with campuses and facilities throughout Pennsylvania. Founded in 1855 as the Farmers’ High School of Pennsylvania, Penn State became the state’s only land-grant university in 1863. Today, Penn State is a major research university which conducts teaching, research, and public service. Its instructional mission includes undergraduate, graduate, professional and continuing education offered through resident instruction and online delivery. In addition to its land-grant designation, it also participates in the sea-grant, space-grant, and sun-grant research consortia; it is one of only four such universities (along with Cornell University(US), Oregon State University(US), and University of Hawaiʻi at Mānoa(US)). Its University Park campus, which is the largest and serves as the administrative hub, lies within the Borough of State College and College Township. It has two law schools: Penn State Law, on the school’s University Park campus, and Dickinson Law, in Carlisle. The College of Medicine is in Hershey. Penn State is one university that is geographically distributed throughout Pennsylvania. There are 19 commonwealth campuses and 5 special mission campuses located across the state. The University Park campus has been labeled one of the “Public Ivies,” a publicly funded university considered as providing a quality of education comparable to those of the Ivy League.

    Annual enrollment at the University Park campus totals more than 46,800 graduate and undergraduate students, making it one of the largest universities in the United States. It has the world’s largest dues-paying alumni association. The university offers more than 160 majors among all its campuses.

    Annually, the university hosts the Penn State IFC/Panhellenic Dance Marathon (THON), which is the world’s largest student-run philanthropy. This event is held at the Bryce Jordan Center on the University Park campus. The university’s athletics teams compete in Division I of the NCAA and are collectively known as the Penn State Nittany Lions, competing in the Big Ten Conference for most sports. Penn State students, alumni, faculty and coaches have received a total of 54 Olympic medals.

    Early years

    The school was sponsored by the Pennsylvania State Agricultural Society and founded as a degree-granting institution on February 22, 1855, by Pennsylvania’s state legislature as the Farmers’ High School of Pennsylvania. The use of “college” or “university” was avoided because of local prejudice against such institutions as being impractical in their courses of study. Centre County, Pennsylvania, became the home of the new school when James Irvin of Bellefonte, Pennsylvania, donated 200 acres (0.8 km2) of land – the first of 10,101 acres (41 km^2) the school would eventually acquire. In 1862, the school’s name was changed to the Agricultural College of Pennsylvania, and with the passage of the Morrill Land-Grant Acts, Pennsylvania selected the school in 1863 to be the state’s sole land-grant college. The school’s name changed to the Pennsylvania State College in 1874; enrollment fell to 64 undergraduates the following year as the school tried to balance purely agricultural studies with a more classic education.

    George W. Atherton became president of the school in 1882, and broadened the curriculum. Shortly after he introduced engineering studies, Penn State became one of the ten largest engineering schools in the nation. Atherton also expanded the liberal arts and agriculture programs, for which the school began receiving regular appropriations from the state in 1887. A major road in State College has been named in Atherton’s honor. Additionally, Penn State’s Atherton Hall, a well-furnished and centrally located residence hall, is named not after George Atherton himself, but after his wife, Frances Washburn Atherton. His grave is in front of Schwab Auditorium near Old Main, marked by an engraved marble block in front of his statue.

    Early 20th century

    In the years that followed, Penn State grew significantly, becoming the state’s largest grantor of baccalaureate degrees and reaching an enrollment of 5,000 in 1936. Around that time, a system of commonwealth campuses was started by President Ralph Dorn Hetzel to provide an alternative for Depression-era students who were economically unable to leave home to attend college.

    In 1953, President Milton S. Eisenhower, brother of then-U.S. President Dwight D. Eisenhower, sought and won permission to elevate the school to university status as The Pennsylvania State University. Under his successor Eric A. Walker (1956–1970), the university acquired hundreds of acres of surrounding land, and enrollment nearly tripled. In addition, in 1967, the Penn State Milton S. Hershey Medical Center, a college of medicine and hospital, was established in Hershey with a $50 million gift from the Hershey Trust Company.

    Modern era

    In the 1970s, the university became a state-related institution. As such, it now belongs to the Commonwealth System of Higher Education. In 1975, the lyrics in Penn State’s alma mater song were revised to be gender-neutral in honor of International Women’s Year; the revised lyrics were taken from the posthumously-published autobiography of the writer of the original lyrics, Fred Lewis Pattee, and Professor Patricia Farrell acted as a spokesperson for those who wanted the change.

    In 1989, the Pennsylvania College of Technology in Williamsport joined ranks with the university, and in 2000, so did the Dickinson School of Law. The university is now the largest in Pennsylvania. To offset the lack of funding due to the limited growth in state appropriations to Penn State, the university has concentrated its efforts on philanthropy.

    Research

    Penn State is classified among “R1: Doctoral Universities – Very high research activity”. Over 10,000 students are enrolled in the university’s graduate school (including the law and medical schools), and over 70,000 degrees have been awarded since the school was founded in 1922.

    Penn State’s research and development expenditure has been on the rise in recent years. For fiscal year 2013, according to institutional rankings of total research expenditures for science and engineering released by the National Science Foundation (US), Penn State stood second in the nation, behind only Johns Hopkins University (US) and tied with the Massachusetts Institute of Technology (US), in the number of fields in which it is ranked in the top ten. Overall, Penn State ranked 17th nationally in total research expenditures across the board. In 12 individual fields, however, the university achieved rankings in the top ten nationally. The fields and sub-fields in which Penn State ranked in the top ten are materials (1st), psychology (2nd), mechanical engineering (3rd), sociology (3rd), electrical engineering (4th), total engineering (5th), aerospace engineering (8th), computer science (8th), agricultural sciences (8th), civil engineering (9th), atmospheric sciences (9th), and earth sciences (9th). Moreover, in eleven of these fields, the university has repeated top-ten status every year since at least 2008. For fiscal year 2011, the National Science Foundation reported that Penn State had spent $794.846 million on R&D and ranked 15th among U.S. universities and colleges in R&D spending.

    For the 2008–2009 fiscal year, Penn State was ranked ninth among U.S. universities by the National Science Foundation, with $753 million in research and development spending for science and engineering. During the 2015–2016 fiscal year, Penn State received $836 million in research expenditures.

    The Applied Research Lab (ARL), located near the University Park campus, has been a research partner with the Department of Defense (US) since 1945 and conducts research primarily in support of the United States Navy. It is the largest component of Penn State’s research efforts statewide, with over 1,000 researchers and other staff members.

    The Materials Research Institute was created to coordinate the highly diverse and growing materials activities across Penn State’s University Park campus. With more than 200 faculty in 15 departments, 4 colleges, and 2 Department of Defense research laboratories, MRI was designed to break down the academic walls that traditionally divide disciplines and enable faculty to collaborate across departmental and even college boundaries. MRI has become a model for this interdisciplinary approach to research, both within and outside the university. Dr. Richard E. Tressler was an international leader in the development of high-temperature materials. He pioneered high-temperature fiber testing and use, advanced instrumentation and test methodologies for thermostructural materials, and design and performance verification of ceramics and composites in high-temperature aerospace, industrial, and energy applications. He was founding director of the Center for Advanced Materials (CAM), which supported many faculty and students from the College of Earth and Mineral Science, the Eberly College of Science, the College of Engineering, the Materials Research Laboratory and the Applied Research Laboratories at Penn State on high-temperature materials. His vision for Interdisciplinary research played a key role in creating the Materials Research Institute, and the establishment of Penn State as an acknowledged leader among major universities in materials education and research.

    The university was one of the founding members of the Worldwide Universities Network (WUN), a partnership that includes 17 research-led universities in the United States, Asia, and Europe. The network provides funding, facilitates collaboration between universities, and coordinates exchanges of faculty members and graduate students among institutions. Former Penn State president Graham Spanier is a former vice-chair of the WUN.

    The Pennsylvania State University Libraries were ranked 14th among research libraries in North America in the 2003–2004 survey released by The Chronicle of Higher Education. The university’s library system began with a 1,500-book library in Old Main. In 2009, its holdings had grown to 5.2 million volumes, in addition to 500,000 maps, five million microforms, and 180,000 films and videos.

    The university’s College of Information Sciences and Technology is the home of CiteSeerX, an open-access repository and search engine for scholarly publications. The university is also the host to the Radiation Science & Engineering Center, which houses the oldest operating university research reactor. Additionally, University Park houses the Graduate Program in Acoustics, the only freestanding acoustics program in the United States. The university also houses the Center for Medieval Studies, a program that was founded to research and study the European Middle Ages, and the Center for the Study of Higher Education (CSHE), one of the first centers established to research postsecondary education.

     
  • richardmitnick 11:28 am on September 4, 2021 Permalink | Reply
    Tags: "Can smartphones affixed to buildings detect earthquakes?", Accelerometers provide between 10 and 30 seconds of warning before the earthquake’s waves arrive., , Earthquake science, , , Smartphones come packaged with GPS location services-constant communication via cell networks-and a device called an accelerometer., Smartphones have all the three components that are there in a scientific grade seismic station., , The accelerometer can record any shaking your phone may experience.   

    From temblor : “Can smartphones affixed to buildings detect earthquakes?” 

    1

    From temblor

    September 1, 2021
    By Meghomita Das, Department of Earth & Planetary Sciences, McGill University (CA).

    Damaging earthquakes can strike at any time, leaving behind a trail of devastation. Recovery from such events can take several years. Unfortunately, scientists cannot forecast the exact time an earthquake will strike. But extensive research in the field of earthquake early warning systems is ongoing. Such systems can provide seconds of warning, which could save lives and prevent people from overwhelming emergency management systems.

    1
    The 2009 Cinchona earthquake, that struck close to the capital city of San Jose, caused 34 fatalities and collapsed houses across Costa Rica. Credit: Capt Diana Parzik, US Army, via Wikipedia, CC-Public Domain Mark 1.0.

    Earthquake early warning systems work by having a densely distributed network of seismic stations capable of rapidly detecting an earthquake, and by sending alerts that warn of shaking to the population. A significant hurdle to designing and implementing such systems is the high cost of installing multiple, scientific-grade seismic stations across earthquake-prone regions. For countries like India or Mexico, which have limited resources and high population densities, these expensive networks are not feasible.

    In a recent study published in AGU Advances, a team of scientists explored whether a low-cost, robust and operational earthquake early warning system — built around comparatively cheap smartphones instead of seismic stations — might become a reality in the near future in Costa Rica, a country that regularly experiences high-magnitude earthquakes. During a six-month testing period, this network, called Alerta Sismica Temprana Utilizando Telefonos Inteligentes (ASTUTI), a collaborative effort between The Geological Survey (US) and the National University of Costa Rica [Universidad Nacional de Costa Rica] (CR), detected and sent alerts for five earthquakes that produced significant shaking in San Jose, Costa Rica’s densely populated capital city.

    Smartphones and earthquakes

    Smartphones come packaged with GPS location services-constant communication via cell networks-and a device called an accelerometer that helps your phone’s screen rotate as you move it around. The accelerometer can also record any shaking your phone may experience. “Essentially, your phone costs maybe $100 and has all the three components that are there in a scientific grade seismic station, which costs thousands of dollars,” says Marino Protti, a study co-author and a seismologist at the Observatorio Vulcanologico y Sismologico de Costa Rica (Universidad Nacional).

    To set up the ASTUTI network, the team deployed 82 Android smartphones, encased in protective boxes, throughout Costa Rica, at an annual cost of $20,000 USD. They installed these smartphones inside buildings, on either the walls or floors of the ground story. The phones are plugged in to AC power supplies.

    The accelerometers stream data via cellular networks in real time to the cloud, says Protti. A cloud-based server receives signals from all stations. So, when an earthquake strikes and four sites detect strong ground motion, an alert goes out to people in San Jose, providing between 10 and 30 seconds of warning before the earthquake’s waves arrive, he explains.

    San Jose’s location relative to the Middle America Trench — where the Cocos Plate dives beneath the Caribbean Plate — is perfect to test the efficacy of this network because the city is in the Goldilocks position. It’s far enough from the trench such that issuing a timely alert is feasible, but close enough such that the population will feel shaking. The ASTUTI network also issued alerts as soon as events were detected, rather than either waiting for an earthquake to grow larger or trying to define its characteristics. This choice gave people more time to protect themselves.

    Did ASTUTI feel it?

    During its six months of operation, a group of people selected to receive alerts via phone were notified of five events that ASTUTI detected, with magnitudes ranging between 4.8 and 5.3. Thirteen earthquakes struck Costa Rica in that time, but the other eight earthquakes did not produce significant shaking to warrant an alert. For two of the five detected events, ASTUTI sent out alerts at the earliest possible time — when the first wave from the earthquake, also called the P-wave — was detected by smartphones. This provided people with enough time to take protective action. Moreover, each of the five detected events were accompanied by a “Did You Feel It” report by the U.S. Geological Survey. This citizen science project collects “felt reports” from people who felt shaking (or didn’t) during earthquakes worldwide. In other words, the earthquakes that shook people enough to file a report were detected by the ASTUTI network.

    3
    One of the ASTUTI earthquake early warning stations. Image on the left shows the encased smartphone, and image on the right shows the software interface that records data from the station. Credit: Brooks et al., 2021, CC-BY-NC-ND 4.0.

    With recent advancements in earthquake early warning, there is a potential for developing a network consisting of expensive high-end devices complemented by a larger number of low-cost devices capable of detecting ground motion, says Raj Prasanna, a telecommunications and electronics engineer and senior lecturer at Massey University-New Zealand [Te Kunenga Ki Pūrehuroa](NZ) who was not involved with this study. “Together, they can become an affordable warning network, with acceptable levels of reliability,” he says.

    In the next phase of development, the team plans to create a hybrid system by integrating this smartphone-enabled network with Costa Rica’s existing scientific-grade seismic network, which will improve the accuracy and reduce time of detection of the earthquake early warning system.

    What the public wants

    Setting up an earthquake early warning system that effectively prompts the public to get to safety is challenging, says Sarah Minson of the USGS, a co-author of the new study. “How do we find out what people want; how do we find out if they are enjoying the system?” she asks. Because earthquake early warning systems are relatively new and people haven’t interacted with them, Minson says, they may not have a personal feel for what works for them. Plus, every country’s needs are different. People’s responses to the same alerts vary depending upon how that specific society culturally reacts to natural hazards.

    To that end, the team plans to develop a smartphone-based application. In the future, they will work with the National Commission for Risk Prevention and Emergency Management in Costa Rica to measure how the Costa Rican population perceives earthquake early warning. The goal, says Protti, is to create a more coordinated response plan for earthquakes in Costa Rica. By coupling effective messaging with earthquake early warning, the public will have crucial seconds to take actions that can protect their lives.

    References

    Brooks, B. A., Protti, M., Ericksen, T., Bunn, J., Vega, F., Cochran, E. S., … & Glennie, C. L. (2021). Robust earthquake early warning at a fraction of the cost: ASTUTI Costa Rica. AGU Advances, 2(3), e2021AV000407.

    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

    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

    QuakeAlertUSA

    1

    About Early Warning Labs, LLC

    Early Warning Labs, LLC (EWL) is an Earthquake Early Warning technology developer and integrator located in Santa Monica, CA. EWL is partnered with industry leading GIS provider ESRI, Inc. and is collaborating with the US Government and university partners.

    EWL is investing millions of dollars over the next 36 months to complete the final integration and delivery of Earthquake Early Warning to individual consumers, government entities, and commercial users.

    EWL’s mission is to improve, expand, and lower the costs of the existing earthquake early warning systems.

    EWL is developing a robust cloud server environment to handle low-cost mass distribution of these warnings. In addition, Early Warning Labs is researching and developing automated response standards and systems that allow public and private users to take pre-defined automated actions to protect lives and assets.

    EWL has an existing beta R&D test system installed at one of the largest studios in Southern California. The goal of this system is to stress test EWL’s hardware, software, and alert signals while improving latency and reliability.

    Earthquake Early Warning Introduction

    The United States Geological Survey (USGS), in collaboration with state agencies, university partners, and private industry, is developing an earthquake early warning system (EEW) for the West Coast of the United States called ShakeAlert. The USGS Earthquake Hazards Program aims to mitigate earthquake losses in the United States. Citizens, first responders, and engineers rely on the USGS for accurate and timely information about where earthquakes occur, the ground shaking intensity in different locations, and the likelihood is of future significant ground shaking.

    The ShakeAlert Earthquake Early Warning System recently entered its first phase of operations. The USGS working in partnership with the California Governor’s Office of Emergency Services (Cal OES) is now allowing for the testing of public alerting via apps, Wireless Emergency Alerts, and by other means throughout California.

    ShakeAlert partners in Oregon and Washington are working with the USGS to test public alerting in those states sometime in 2020.

    ShakeAlert has demonstrated the feasibility of earthquake early warning, from event detection to producing USGS issued ShakeAlerts ® and will continue to undergo testing and will improve over time. In particular, robust and reliable alert delivery pathways for automated actions are currently being developed and implemented by private industry partners for use in California, Oregon, and Washington.

    Earthquake Early Warning Background

    The objective of an earthquake early warning system is to rapidly detect the initiation of an earthquake, estimate the level of ground shaking intensity to be expected, and issue a warning before significant ground shaking starts. A network of seismic sensors detects the first energy to radiate from an earthquake, the P-wave energy, and the location and the magnitude of the earthquake is rapidly determined. Then, the anticipated ground shaking across the region to be affected is estimated. The system can provide warning before the S-wave arrives, which brings the strong shaking that usually causes most of the damage. Warnings will be distributed to local and state public emergency response officials, critical infrastructure, private businesses, and the public. EEW systems have been successfully implemented in Japan, Taiwan, Mexico, and other nations with varying degrees of sophistication and coverage.

    Earthquake early warning can provide enough time to:

    Instruct students and employees to take a protective action such as Drop, Cover, and Hold On
    Initiate mass notification procedures
    Open fire-house doors and notify local first responders
    Slow and stop trains and taxiing planes
    Install measures to prevent/limit additional cars from going on bridges, entering tunnels, and being on freeway overpasses before the shaking starts
    Move people away from dangerous machines or chemicals in work environments
    Shut down gas lines, water treatment plants, or nuclear reactors
    Automatically shut down and isolate industrial systems

    However, earthquake warning notifications must be transmitted without requiring human review and response action must be automated, as the total warning times are short depending on geographic distance and varying soil densities from the epicenter.

     
  • richardmitnick 9:45 am on September 4, 2021 Permalink | Reply
    Tags: "Ground-breaking work from SFU identifies new source for earthquakes and tsunamis in the Greater Tokyo Region", A previously unconsidered plate boundary, Earthquake science, In 2011 eastern Japan was hit with a massive magnitude 9 quake – creating the largest rupture area of any earthquake originating from the Japan Trench., Paleoecology, ,   

    From Simon Fraser University (CA) : “Ground-breaking work from SFU identifies new source for earthquakes and tsunamis in the Greater Tokyo Region” 

    From Simon Fraser University (CA)

    September 02, 2021
    Diane Mar-Nicolle

    1
    Jessica Pilarczyk and colleagues from the Geological Survey of Japan core rice paddies on the Boso peninsula to uncover geological evidence for a tsunami from 1,000 years ago. Credit: SFU.

    Researchers have discovered geologic evidence that unusually large earthquakes and tsunamis from the Tokyo region—located near tectonic plate boundaries that are recognized as a seismic hazard source—may be traceable to a previously unconsidered plate boundary. The team, headed by Simon Fraser University Earth scientist Jessica Pilarczyk, has published its research today in Nature Geoscience.

    The team’s ground-breaking discovery represents a new and unconsidered seismic risk for Japan with implications for countries lining the Pacific Rim, including Canada.

    Pilarczyk points to low-lying areas like Delta, Richmond and Port Alberni as potentially vulnerable to tsunamis originating from this region.

    In 2011 eastern Japan was hit with a massive magnitude 9 quake – creating the largest rupture area of any earthquake originating from the Japan Trench. It triggered the Fukushima Daiichi nuclear disaster and a tsunami that travelled thousands of miles away—impacting the shores of British Columbia, California, Oregon, Hawaii and Chile.

    For the past decade, Pilarczyk and an international team of collaborators have been working with The Geological Survey of Japan, AIST|産総研 地質調査総合センタ](JP) to study Japan’s unique geologic history. Together, they uncovered and analyzed sandy deposits from the Boso Peninsula region (50 km east of Tokyo) that they attribute to an unusually large tsunami that occurred about 1,000 years ago.

    Until now, scientists did not have historical records to ascertain if a portion of the Philippine Sea/Pacific plate boundary near the Boso Peninsula was capable of generating large tsunamis similar in size as the Tohoku event in 2011.

    Using a combination of radiocarbon dating, geologic and historical records, and paleoecology, the team used 13 hypothetical and historical models to assess each of the three plate boundaries, including the Continental/Philippine Sea plate boundary (Sagami Trough), the Continental/Pacific plate boundary (Japan Trench) and the Philippine Sea/Pacific plate boundary (Izu-Bonin Trench) as sources of the 1,000-year-old earthquake.

    2
    Jessica Pilarczyk (SFU) and collaborator Tina Dura (The Virginia Polytechnic Institute and State University (US)) sample sediment cores from rice paddies of the Greater Tokyo Region that contain evidence for an earthquake from 1,000 years ago that potentially originated from a historically unconsidered earthquake source. Credit: SFU.

    Pilarczyk reports that the modeled scenarios suggest that the source of the tsunami from 1,000 years ago originated from the offshore area off the Boso Peninsula — the smallest of which (for example, possible earthquakes with the lowest minimum magnitude), are linked to the previously unconsidered Izu-Bonin Trench at the boundary of the Philippine Sea and Pacific plates.

    “Earthquake hazard assessments for the Tokyo region are complicated by the’ trench-trench triple junction’, where the oceanic Philippine Sea Plate not only underthrusts a continental plate but is also being subducted by the Pacific Plate.”says Pilarczyk, an assistant professor of Earth sciences at SFU who holds a Canada Research Chair in Natural Hazards. ”Great thrust earthquakes and associated tsunamis are historically recognized hazards from the Continental/Philippine Sea (Sagami Trough) and Continental/Pacific (Japan Trench) plate boundaries but not from the Philippine Sea/Pacific boundary alone.”

    Pilarczyk hopes that these findings will be used to produce better informed seismic hazard maps for Japan. She also says that this information could be used by far-field locations, including Canada, to inform building practices and emergency management strategies that would help mitigate the destructive consequences of an earthquake similar to the one of 1,000 years ago.

    See the full article here.

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Simon Fraser University (CA) is a public research university in British Columbia, Canada, with three campuses: Burnaby (main campus), Surrey, and Vancouver. The 170-hectare (420-acre) main Burnaby campus on Burnaby Mountain, located 20 kilometres (12 mi) from downtown Vancouver, was established in 1965 and comprises more than 30,000 students and 160,000 alumni. The university was created in an effort to expand higher education across Canada.

    Simon Fraser University (CA) is a member of multiple national and international higher education, including the Association of Commonwealth Universities, International Association of Universities, and Universities Canada (CA). Simon Fraser University has also partnered with other universities and agencies to operate joint research facilities such as the TRIUMF- Canada’s particle accelerator centre [Centre canadien d’accélération des particules] (CA) for particle and nuclear physics, which houses the world’s largest cyclotron, and Bamfield Marine Station, a major centre for teaching and research in marine biology.

    Undergraduate and graduate programs at Simon Fraser University (CA) operate on a year-round, three-semester schedule. Consistently ranked as Canada’s top comprehensive university and named to the Times Higher Education list of 100 world universities under 50, Simon Fraser University (CA)is also the first Canadian member of the National Collegiate Athletic Association, the world’s largest college sports association. In 2015, Simon Fraser University (CA) became the second Canadian university to receive accreditation from the Northwest Commission on Colleges and Universities. Simon Fraser University (CA) faculty and alumni have won 43 fellowships to the Royal Society of Canada [Société royale du Canada](CA), three Rhodes Scholarships and one Pulitzer Prize. Among the list of alumni includes two former premiers of British Columbia, Gordon Campbell and Ujjal Dosanjh, owner of the Vancouver Canucks NHL team, Francesco Aquilini, Prime Minister of Lesotho, Pakalitha Mosisili, director at the Max Planck Society [Max Planck Gesellschaft](DE) , Robert Turner, and humanitarian and cancer research activist, Terry Fox.

     
  • richardmitnick 2:16 pm on August 28, 2021 Permalink | Reply
    Tags: "Earthquake swarm rocks the ground at Hawai'i's Kilauea volcano", , , Earthquake science, , ,   

    From Live Science (US): “Earthquake swarm rocks the ground at Hawaii’s Kilauea volcano” 

    From Live Science (US)

    8.27.21
    Harry Baker

    1
    A lava lake inside the Pu’u ‘Ō’ō crater in Kilauea’s’ eastern rift zone during a previous eruption. (Image credit: Shutterstock)

    Kilauea volcano gave scientists and local Hawaiians a scare this week, when a swarm of more than 140 earthquakes in just 12 hours prompted authorities to raise the alarm over a possible imminent eruption.

    But now, Kilauea’s brief rumble is over; the volcano did not erupt and is barely registering any earthquakes.

    The Geological Survey (US) made this report on Thursday (Aug. 26).

    However, Kilauea’s flare of activity set scientists on edge. The earthquake swarm occurred between 4:30 p.m. local time (10:30 p.m. EDT) Monday (Aug. 23) and 4:30 a.m. local time (10:30 a.m. EDT) Tuesday (Aug. 24) beneath the south part of Kilauea’s summit caldera, with a peak in activity around 1:30 a.m. local time (7:30 a.m. EDT) Wednesday.

    This is according to the USGS.

    The earthquakes were tiny; most registered at below magnitude 1.0, with the most violent reaching magnitude 3.3. The tectonic activity also coincided with a shift in the ground formation to the west of the swarm, which the USGS said “may indicate an intrusion of magma occurring about 0.6 to 1.2 miles (1 to 2 kilometers) beneath the south caldera.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 1:05 pm on August 28, 2021 Permalink | Reply
    Tags: "Geophysicist sprints to monitor quake aftershocks in Alaska", An 8.2-magnitude earthquake struck off the coast of Chignik Alaska on July 29 2021., , , , Earthquake science, , This was the biggest earthquake in the U.S. since 1965.   

    From Cornell Chronicle (US) : “Geophysicist sprints to monitor quake aftershocks in Alaska” 

    From Cornell Chronicle (US)

    August 27, 2021
    David Nutt
    cunews@cornell.edu

    1
    Geoffrey Abers, the William and Katherine Snee Professor in Geological Sciences, deploys a temporary seismometer on Kodiak Island in August. Provided.

    When an 8.2-magnitude earthquake struck off the coast of Chignik Alaska on July 29 2021 geophysicist Geoffrey Abers did the logical – if not simple – thing.

    He raced to Alaska with a group of collaborators to record its aftershocks.

    The data they collect could provide new insight into the mechanics of crustal faults and possibly help researchers understand and anticipate future earthquake clusters.

    “This was the biggest earthquake in the U.S. since 1965,” said Abers, the William and Katherine Snee Professor in Geological Sciences and chair of the Department of Earth and Atmospheric Sciences in the College of Engineering. “There are very few good recordings of earthquakes this large anywhere on the planet. So that’s a big motivation for trying to understand the sequence as sort of an archetype. We know enough about the area and its past history that we can put it in context.”

    Because Alaska rests atop a subduction zone, where it is regularly jarred by shifting tectonic plates, the country is a wellspring of seismic activity, and Abers has been studying its earthquakes for three decades.

    In 2017, he led the Alaska Amphibious Community Seismic Experiment (AACSE), a $4.5 million project that deployed 105 high-end seismometers along a 435-mile-long stretch of the Alaska peninsula’s coast.

    The July 29 quake had a whiff of déjà vu. It occurred in almost the exact same spot as the AACSE research.

    “I thought if anybody’s going to figure this out, it’s us, because we know the logistics of it,” he said.

    Unfortunately, the AACSE seismometers had been collected in 2019 to harvest the data, which meant Abers and his collaborators needed to acquire new instrumentation more or less from scratch. On the plus side, they knew precisely where to put it all. They just needed to get there quickly.

    “You’re racing against time because every day there are fewer aftershocks on average. That happens less and less the longer you wait,” he said.

    Abers reconnected with his main AACSE collaborator, Jeff Freymueller, a geodesy specialist at The Michigan State University (US), and researchers with The University of Alaska-Fairbanks (US), The University of California- Santa Cruz (US) and The University of Colorado-Boulder (US). The team received a $154,000 rapid grant from The National Science Foundation (US), which had funded the AACSE. For their equipment, they turned to the IRIS Program for the Array Seismic Studies of the Continental Lithosphere (PASSCAL) instrument center, an NSF-supported user facility at The New Mexico Institute of Mining and Technology (US).

    “This all happened really fast. It’s kind of a blur,” Abers said. “Almost literally at the 11th hour, we were still assembling the team of people.”

    The researchers began arriving in Alaska on Aug. 8. Abers spent several days deploying five temporary seismometers on Kodiak Island. Each seismometer consists of a sensor, roughly the size of a large coffee mug, that is buried about two feet underground and connected by cable to a data logger, which converts electrical signals to digital bits and stores them on a disk. The units are powered by air-alkaline technology that keeps the seismographs running all year. The electronics and batteries are housed in sturdy aluminum boxes, specially designed to resist the prying paws of the numerous brown bears on the island.

    Freymueller’s group traveled further out on the Alaska Peninsula to install continuous GPS sites that will record post-seismic movements with precise timing, as well as additional seismometers.

    The team also revived their old AACSE blog to document their efforts.

    By Aug. 18, the researchers were returning home. They won’t be able to analyze their data until they travel to Alaska in late spring to collect the instruments. Their data will be sent to the IRIS Data Management Center, where it will be publicly accessible for anyone interested.

    “The Alaska peninsula section has been especially interesting,” Abers said. “These plates are steadily converging. The stresses are building up. This is the place it’s been the longest since the last big earthquake (circa 1938), so seems like the most likely for the next one.”

    Abers once thought of earthquake prediction as a “fool’s errand,” but he’s become more optimistic that by understanding how stresses can spread to other segments, seismologists may be able to develop a mechanism for specific causal prediction.

    While the team must wait until next year to reap the full rewards of their research, they did experience seismic activity in real time. At least some of them did.

    “There was a 6.9 aftershock while we were up there,” Abers said. “But it was the middle of the night, so I slept through it.”

    See the full article here .


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

    Please help promote STEM in your local schools.


    Stem Education Coalition

    Once called “the first American university” by educational historian Frederick Rudolph, Cornell University represents a distinctive mix of eminent scholarship and democratic ideals. Adding practical subjects to the classics and admitting qualified students regardless of nationality, race, social circumstance, gender, or religion was quite a departure when Cornell was founded in 1865.

    Today’s Cornell reflects this heritage of egalitarian excellence. It is home to the nation’s first colleges devoted to hotel administration, industrial and labor relations, and veterinary medicine. Both a private university and the land-grant institution of New York State, Cornell University is the most educationally diverse member of the Ivy League.

    On the Ithaca campus alone nearly 20,000 students representing every state and 120 countries choose from among 4,000 courses in 11 undergraduate, graduate, and professional schools. Many undergraduates participate in a wide range of interdisciplinary programs, play meaningful roles in original research, and study in Cornell programs in Washington, New York City, and the world over.

    Cornell University (US) is a private, statutory, Ivy League and land-grant research university in Ithaca, New York. Founded in 1865 by Ezra Cornell and Andrew Dickson White, the university was intended to teach and make contributions in all fields of knowledge—from the classics to the sciences, and from the theoretical to the applied. These ideals, unconventional for the time, are captured in Cornell’s founding principle, a popular 1868 quotation from founder Ezra Cornell: “I would found an institution where any person can find instruction in any study.”

    The university is broadly organized into seven undergraduate colleges and seven graduate divisions at its main Ithaca campus, with each college and division defining its specific admission standards and academic programs in near autonomy. The university also administers two satellite medical campuses, one in New York City and one in Education City, Qatar, and Jacobs Technion-Cornell Institute(US) in New York City, a graduate program that incorporates technology, business, and creative thinking. The program moved from Google’s Chelsea Building in New York City to its permanent campus on Roosevelt Island in September 2017.

    Cornell is one of the few private land grant universities in the United States. Of its seven undergraduate colleges, three are state-supported statutory or contract colleges through the SUNY – The State University of New York (US) system, including its Agricultural and Human Ecology colleges as well as its Industrial Labor Relations school. Of Cornell’s graduate schools, only the veterinary college is state-supported. As a land grant college, Cornell operates a cooperative extension outreach program in every county of New York and receives annual funding from the State of New York for certain educational missions. The Cornell University Ithaca Campus comprises 745 acres, but is much larger when the Cornell Botanic Gardens (more than 4,300 acres) and the numerous university-owned lands in New York City are considered.

    Alumni and affiliates of Cornell have reached many notable and influential positions in politics, media, and science. As of January 2021, 61 Nobel laureates, four Turing Award winners and one Fields Medalist have been affiliated with Cornell. Cornell counts more than 250,000 living alumni, and its former and present faculty and alumni include 34 Marshall Scholars, 33 Rhodes Scholars, 29 Truman Scholars, 7 Gates Scholars, 55 Olympic Medalists, 10 current Fortune 500 CEOs, and 35 billionaire alumni. Since its founding, Cornell has been a co-educational, non-sectarian institution where admission has not been restricted by religion or race. The student body consists of more than 15,000 undergraduate and 9,000 graduate students from all 50 American states and 119 countries.

    History

    Cornell University was founded on April 27, 1865; the New York State (NYS) Senate authorized the university as the state’s land grant institution. Senator Ezra Cornell offered his farm in Ithaca, New York, as a site and $500,000 of his personal fortune as an initial endowment. Fellow senator and educator Andrew Dickson White agreed to be the first president. During the next three years, White oversaw the construction of the first two buildings and traveled to attract students and faculty. The university was inaugurated on October 7, 1868, and 412 men were enrolled the next day.

    Cornell developed as a technologically innovative institution, applying its research to its own campus and to outreach efforts. For example, in 1883 it was one of the first university campuses to use electricity from a water-powered dynamo to light the grounds. Since 1894, Cornell has included colleges that are state funded and fulfill statutory requirements; it has also administered research and extension activities that have been jointly funded by state and federal matching programs.

    Cornell has had active alumni since its earliest classes. It was one of the first universities to include alumni-elected representatives on its Board of Trustees. Cornell was also among the Ivies that had heightened student activism during the 1960s related to cultural issues; civil rights; and opposition to the Vietnam War, with protests and occupations resulting in the resignation of Cornell’s president and the restructuring of university governance. Today the university has more than 4,000 courses. Cornell is also known for the Residential Club Fire of 1967, a fire in the Residential Club building that killed eight students and one professor.

    Since 2000, Cornell has been expanding its international programs. In 2004, the university opened the Weill Cornell Medical College in Qatar. It has partnerships with institutions in India, Singapore, and the People’s Republic of China. Former president Jeffrey S. Lehman described the university, with its high international profile, a “transnational university”. On March 9, 2004, Cornell and Stanford University(US) laid the cornerstone for a new ‘Bridging the Rift Center’ to be built and jointly operated for education on the Israel–Jordan border.

    Research

    Cornell, a research university, is ranked fourth in the world in producing the largest number of graduates who go on to pursue PhDs in engineering or the natural sciences at American institutions, and fifth in the world in producing graduates who pursue PhDs at American institutions in any field. Research is a central element of the university’s mission; in 2009 Cornell spent $671 million on science and engineering research and development, the 16th highest in the United States. Cornell is classified among “R1: Doctoral Universities – Very high research activity”.

    For the 2016–17 fiscal year, the university spent $984.5 million on research. Federal sources constitute the largest source of research funding, with total federal investment of $438.2 million. The agencies contributing the largest share of that investment are the Department of Health and Human Services and the National Science Foundation(US), accounting for 49.6% and 24.4% of all federal investment, respectively. Cornell was on the top-ten list of U.S. universities receiving the most patents in 2003, and was one of the nation’s top five institutions in forming start-up companies. In 2004–05, Cornell received 200 invention disclosures; filed 203 U.S. patent applications; completed 77 commercial license agreements; and distributed royalties of more than $4.1 million to Cornell units and inventors.

    Since 1962, Cornell has been involved in unmanned missions to Mars. In the 21st century, Cornell had a hand in the Mars Exploration Rover Mission. Cornell’s Steve Squyres, Principal Investigator for the Athena Science Payload, led the selection of the landing zones and requested data collection features for the Spirit and Opportunity rovers. NASA-JPL/Caltech(US) engineers took those requests and designed the rovers to meet them. The rovers, both of which have operated long past their original life expectancies, are responsible for the discoveries that were awarded 2004 Breakthrough of the Year honors by Science. Control of the Mars rovers has shifted between National Aeronautics and Space Administration(US)’s JPL-Caltech (US) and Cornell’s Space Sciences Building.

    Further, Cornell researchers discovered the rings around the planet Uranus, and Cornell built and operated the telescope at Arecibo Observatory located in Arecibo, Puerto Rico(US) until 2011, when they transferred the operations to SRI International, the Universities Space Research Association (US) and the Metropolitan University of Puerto Rico [Universidad Metropolitana de Puerto Rico](US).

    The Automotive Crash Injury Research Project was begun in 1952. It pioneered the use of crash testing, originally using corpses rather than dummies. The project discovered that improved door locks; energy-absorbing steering wheels; padded dashboards; and seat belts could prevent an extraordinary percentage of injuries.

    In the early 1980s, Cornell deployed the first IBM 3090-400VF and coupled two IBM 3090-600E systems to investigate coarse-grained parallel computing. In 1984, the National Science Foundation began work on establishing five new supercomputer centers, including the Cornell Center for Advanced Computing, to provide high-speed computing resources for research within the United States. As an National Science Foundation (US) center, Cornell deployed the first IBM Scalable Parallel supercomputer.

    In the 1990s, Cornell developed scheduling software and deployed the first supercomputer built by Dell. Most recently, Cornell deployed Red Cloud, one of the first cloud computing services designed specifically for research. Today, the center is a partner on the National Science Foundation XSEDE-Extreme Science Engineering Discovery Environment supercomputing program, providing coordination for XSEDE architecture and design, systems reliability testing, and online training using the Cornell Virtual Workshop learning platform.

    Cornell scientists have researched the fundamental particles of nature for more than 70 years. Cornell physicists, such as Hans Bethe, contributed not only to the foundations of nuclear physics but also participated in the Manhattan Project. In the 1930s, Cornell built the second cyclotron in the United States. In the 1950s, Cornell physicists became the first to study synchrotron radiation.

    During the 1990s, the Cornell Electron Storage Ring, located beneath Alumni Field, was the world’s highest-luminosity electron-positron collider. After building the synchrotron at Cornell, Robert R. Wilson took a leave of absence to become the founding director of DOE’s Fermi National Accelerator Laboratory(US), which involved designing and building the largest accelerator in the United States.

    Cornell’s accelerator and high-energy physics groups are involved in the design of the proposed ILC-International Linear Collider(JP) and plan to participate in its construction and operation. The International Linear Collider(JP), to be completed in the late 2010s, will complement the CERN Large Hadron Collider(CH) and shed light on questions such as the identity of dark matter and the existence of extra dimensions.

    As part of its research work, Cornell has established several research collaborations with universities around the globe. For example, a partnership with the University of Sussex(UK) (including the Institute of Development Studies at Sussex) allows research and teaching collaboration between the two institutions.

     
  • richardmitnick 3:47 pm on August 27, 2021 Permalink | Reply
    Tags: , , Earthquake science, , , Scientists surveying the seabed off New Zealand’s east coast have uncovered undersea mountains that help explain mysterious slow-motion earthquakes., So why do some faults slip suddenly and set off deadly earthquakes while others slide slowly and stealthily?, , The Hikurangi Margin zone poses a significant earthquake and tsunami hazard to coastal communities in New Zealand but the largest earthquakes only seem to occur toward the south of the margin., The team used electromagnetic methods to essentially take an MRI scan of the seabed along the Hikurangi Margin where the Pacific Plate dives beneath the Australian Plate., This study is the first to use electromagnetic methods to map out water trapped in rocks beneath the seafloor offshore.   

    From temblor : “Submarine mountains can subdue earthquakes” 

    1

    From temblor

    August 23, 2021

    Scientists surveying the seabed off New Zealand’s east coast have uncovered undersea mountains that help explain mysterious slow-motion earthquakes.

    By Erin Martin-Jones, Ph.D., Department of Earth Sciences, University of Cambridge (UK)

    Earth’s tectonic plates are constantly jostling for space — colliding and diving under one another in a dance that sculpts dramatic mountain chains, fuels volcanic eruptions and delivers earth-shattering tremors. But sometimes these forces can have more subtle impacts. Take, for instance, silent earthquakes or “slow-slip events,” which can move at slow-motion speeds, stretching their ruptures over weeks to months. Often, no one feels a thing, and these events go undetected even by seismometers.

    So why do some faults slip suddenly and set off deadly earthquakes while others slide slowly and stealthily? A new study [Nature] suggests that off the coast of New Zealand, where thousands of small quakes occur each year, excess water locked within undersea mountains, or “seamounts,” can promote the silent sliding linked to slow-motion earthquakes.

    2
    Map of Hikurangi Subduction Zone, showing locations where electromagnetic receivers were deployed to collect data. Credit: Christine Chesley, using GeoMapApp and data from William Ryan et al., Geochemistry, Geophysics, Geosystems (2009).

    The Hikurangi Margin Subduction Zone

    To understand slow-slip earthquakes off New Zealand’s eastern coast, a team of researchers led by Christine Chesley of Columbia University’s Lamont-Doherty Earth Observatory first had to figure out a way to peer into the depths of a subduction zone.

    The team used electromagnetic methods to essentially take an MRI scan of the seabed along the Hikurangi Margin where the Pacific Plate dives beneath the Australian Plate. That subduction motion along the margin is partly responsible for the more than 15,000 earthquakes in the region each year. Most are so small that they go unnoticed, but between 150 and 200 are large enough to be felt.

    3
    The research vessel hauls in one of the receivers used to take electromagnetic measurements of the seabed. Credit: Kerry Key.

    This subduction zone poses a significant earthquake and tsunami hazard to coastal communities in New Zealand, but the largest earthquakes only seem to occur toward the south of the margin — and scientists want to know why. “One of the fascinating things about this area, and why so many have studied it, is the puzzling variation in earthquake hazards over a very small area,” Chesley says.

    Although large earthquakes haven’t struck the North Island in roughly the last 200 years, evidence of ancient quakes is written in the rocks along the coastline, which have been jolted upward by past seismic events.

    Diving beneath the hidden depths of silent earthquakes

    In December 2018, the research team began a month-long deep-sea cruise, collecting profiles of the seafloor in the northern part of the subduction zone margin, which is studded with large seamounts. “Although other studies have suggested that seamounts may contribute to small, rather than large and destructive earthquakes, it’s been unclear exactly how those mountains interact with the seafloor as they are subducted,” says Chesley.

    Chesley’s eye was drawn to two seamounts: the Tūranganui Knoll, located about 110 kilometers southeast of the east coast city of Gisborne, and an unnamed one that is closer to the margin and is currently being subducted. A cluster of tiny earthquakes related to a 2014 slow-slip event occurred around the second seamount, which first began subducting about a million years ago.

    5
    Christine Chesley and Eric Attias operate the Scripps Undersea Electromagnetic Source Instrument (SUESI) during a deep-tow. SUESI is attached to the ship via a coaxial cable and must be “flown” about 100 meters above the seafloor. Credit: Kerry Key.

    Peeling back the layers of a seamount

    Chesley’s team’s electric conductivity survey revealed that each seamount was made up of layers of varying porosity, which held water and conducted electricity differently. Each had a solid core surrounded by a layer of loose, cindery material that acts a bit like a sponge. In fact, the team found that seamounts lock away three to five times more water than typical oceanic crust. This water can act as a lubricant to help tectonic plates glide into Earth’s interior without setting off a large earthquake.

    “It makes a lot of sense, knowing how they form, but we really weren’t expecting them to be such heterogeneous masses of rock,” says Chesley. She noted that the nuance in material can really affect how the subducting plate moves and expels water when it is subducted.

    Because both seamounts had a similar structure, the researchers think that even actively subducting seamounts retain their structural strength — so much so that they can damage the overriding plate, causing tiny faults that dissipate the energy and result in slow-slip events.

    New methods

    This study is the first to use electromagnetic methods to map out water trapped in rocks beneath the seafloor offshore, says Susan Ellis, a geophysicist at GNS Science, who was not involved in the study. “Mapping the structure of the seafloor is extremely challenging and has only recently become viable. This research is at the cutting edge of new geophysical imaging methods,” Ellis says.

    3
    Electromagnetic receivers can be seen on the back deck of the R/V Roger Revelle during particularly rough seas. Credit: Kerry Key.

    “These results are very exciting … they show just how subducting topography can impact water content,” she adds. That, in turn, reveals the type of slipping. “Understanding why slow-slip events occur is critical for estimating New Zealand’s earthquake and tsunami hazard.”

    Factoring underwater oddities into hazard models

    “Seamounts are very common on the seafloor, but hazard models currently don’t consider how they contribute to slow-slip events,” says Chesley. “Now we know that we need to take seafloor topography into account — otherwise we’re not getting the full picture.”

    But Chesley and her team note that slow-slip earthquakes aren’t always subdued. In 1947, two unusual tsunamis were both associated with slow-slip behavior. And because they weren’t preceded by shaking, there was little warning.

    “Future work in other locations of the margin, and in other subduction zones with and without seamounts, will help us understand whether there are any other factors that also contribute to slow-slip events,” says Ellis. Or that contribute to a larger event, for that matter.

    References:

    Chesley, C., Naif, S., Key, K., & Bassett, D. (2021). Fluid-rich subducting topography generates anomalous forearc porosity. Nature, 595(7866), 255-260. doi.org/10.1038/s41586-021-03619-8

    Sun, T., Saffer, D. and Ellis, S., 2020. Mechanical and hydrological effects of seamount subduction on megathrust stress and slip. Nature Geoscience, 13(3), pp.249-255. doi.org/10.1038/s41561-020-0566-5

    Wallace, L.M., Webb, S.C., Ito, Y., Mochizuki, K., Hino, R., Henrys, S., Schwartz, S.Y. and Sheehan, A.F., 2016. Slow slip near the trench at the Hikurangi subduction zone, New Zealand. Science, 352(6286), pp.701-704. doi.org/10.1126/science.aaf2349

    Wang, K., & Bilek, S. L. (2011). Do subducting seamounts generate or stop large earthquakes? Geology, 39(9), 819-822. doi.org/10.1130/G31856.1

    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 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

    QuakeAlertUSA

    1

    About Early Warning Labs, LLC

    Early Warning Labs, LLC (EWL) is an Earthquake Early Warning technology developer and integrator located in Santa Monica, CA. EWL is partnered with industry leading GIS provider ESRI, Inc. and is collaborating with the US Government and university partners.

    EWL is investing millions of dollars over the next 36 months to complete the final integration and delivery of Earthquake Early Warning to individual consumers, government entities, and commercial users.

    EWL’s mission is to improve, expand, and lower the costs of the existing earthquake early warning systems.

    EWL is developing a robust cloud server environment to handle low-cost mass distribution of these warnings. In addition, Early Warning Labs is researching and developing automated response standards and systems that allow public and private users to take pre-defined automated actions to protect lives and assets.

    EWL has an existing beta R&D test system installed at one of the largest studios in Southern California. The goal of this system is to stress test EWL’s hardware, software, and alert signals while improving latency and reliability.

    Earthquake Early Warning Introduction

    The United States Geological Survey (USGS), in collaboration with state agencies, university partners, and private industry, is developing an earthquake early warning system (EEW) for the West Coast of the United States called ShakeAlert. The USGS Earthquake Hazards Program aims to mitigate earthquake losses in the United States. Citizens, first responders, and engineers rely on the USGS for accurate and timely information about where earthquakes occur, the ground shaking intensity in different locations, and the likelihood is of future significant ground shaking.

    The ShakeAlert Earthquake Early Warning System recently entered its first phase of operations. The USGS working in partnership with the California Governor’s Office of Emergency Services (Cal OES) is now allowing for the testing of public alerting via apps, Wireless Emergency Alerts, and by other means throughout California.

    ShakeAlert partners in Oregon and Washington are working with the USGS to test public alerting in those states sometime in 2020.

    ShakeAlert has demonstrated the feasibility of earthquake early warning, from event detection to producing USGS issued ShakeAlerts ® and will continue to undergo testing and will improve over time. In particular, robust and reliable alert delivery pathways for automated actions are currently being developed and implemented by private industry partners for use in California, Oregon, and Washington.

    Earthquake Early Warning Background

    The objective of an earthquake early warning system is to rapidly detect the initiation of an earthquake, estimate the level of ground shaking intensity to be expected, and issue a warning before significant ground shaking starts. A network of seismic sensors detects the first energy to radiate from an earthquake, the P-wave energy, and the location and the magnitude of the earthquake is rapidly determined. Then, the anticipated ground shaking across the region to be affected is estimated. The system can provide warning before the S-wave arrives, which brings the strong shaking that usually causes most of the damage. Warnings will be distributed to local and state public emergency response officials, critical infrastructure, private businesses, and the public. EEW systems have been successfully implemented in Japan, Taiwan, Mexico, and other nations with varying degrees of sophistication and coverage.

    Earthquake early warning can provide enough time to:

    Instruct students and employees to take a protective action such as Drop, Cover, and Hold On
    Initiate mass notification procedures
    Open fire-house doors and notify local first responders
    Slow and stop trains and taxiing planes
    Install measures to prevent/limit additional cars from going on bridges, entering tunnels, and being on freeway overpasses before the shaking starts
    Move people away from dangerous machines or chemicals in work environments
    Shut down gas lines, water treatment plants, or nuclear reactors
    Automatically shut down and isolate industrial systems

    However, earthquake warning notifications must be transmitted without requiring human review and response action must be automated, as the total warning times are short depending on geographic distance and varying soil densities from the epicenter.

     
  • richardmitnick 2:41 pm on August 20, 2021 Permalink | Reply
    Tags: "Swipe Left on the 'Big One' Better Dates for Cascadia Quakes", , , Coseismic coastal deformation, , Earthquake science, , Geochronometers, Geologic proxies of megathrust earthquakes are generated by different aspects of the rupture process and can therefore inform us about specific rupture characteristics and hazards., , Ghost forests, New data collections from coastal forests that perished in or survived through CSZ earthquakes can now give near-annual dates for both inundations and ecosystem transitions., , , The last behemoth earthquake on the CSZ estimated at magnitude 9 struck on 26 January 1700.   

    From Eos: “Swipe Left on the ‘Big One’- Better Dates for Cascadia Quakes” 

    From AGU
    Eos news bloc

    From Eos

    8.20.21
    Jessie K. Pearl
    Lydia Staisch
    lstaisch@usgs.gov

    1
    The dead trees in this ghost forest in Copalis, Wash., were killed during the last major Cascadia earthquake in January 1700. Credit: Jessie K. Pearl. [Ed.: If it was 1700 C.E., how are they still standing?]

    The CSZ is a tectonic boundary off the coast that has unleashed massive earthquakes and tsunamis as the Juan de Fuca Plate is thrust beneath the North American Plate. And it will do so again. But when? And how big will the earthquake—or earthquakes—be?

    The last behemoth earthquake on the CSZ estimated at magnitude 9 struck on 26 January 1700. We know this age with such precision—unique in paleoseismology—because of several lines of geologic proxy evidence that coalesce around that date, in addition to Japanese historical records describing an “orphan tsunami” (a tsunami with no corresponding local earthquake) on that particular date [Atwater et al., 2015*]. Indigenous North American oral histories also describe the event. Geoscientists have robust evidence for other large earthquakes in Cascadia’s past; however, deciphering and precisely dating the geologic record become more difficult the farther back in time you go.

    *All cited works in References below.

    Precision dating of and magnitude constraints on past earthquakes are critically important for assessing modern CSZ earthquake hazards. Such estimates require knowledge of the area over which the fault has broken in the past; the amount of displacement, or slip, on the fault; the speed at which slip occurred; and the timing of events and their potential to occur in rapid succession (called clustering). The paucity of recent seismicity on the CSZ means our understanding of earthquake recurrence there primarily comes from geologic earthquake proxies, including evidence of coseismic land level changes, tsunami inundations, and strong shaking found in onshore and marine environments (Figure 1). Barring modern earthquakes, increasing the accuracy and precision of paleoseismological records is the only way to better constrain the size and frequency of megathrust ruptures and to improve our understanding of natural variability in CSZ earthquake hazards.

    1
    Fig. 1. Age ranges obtained from different geochronologic methods used for estimating Cascadia Subduction Zone megathrust events are shown in this diagram of preservation environments. At top is a dendrochronological analysis comparing a tree killed from a megathrust event with a living specimen. Here ^14C refers to radiocarbon (or carbon-14), and “wiggle-match ^14C” refers to an age model based on multiple, relatively dated (exact number of years known between samples) annual tree ring samples. Schematic sedimentary core observations and sample locations are shown for marsh and deep-sea marine environments. Gray probability distributions for examples of each 14C method are shown to the right of the schematic cores, with 95% confidence ranges in brackets. Optically stimulated luminescence (OSL)-based estimates are shown as a gray dot with error bars.

    To discuss ideas, frontiers, and the latest research at the intersection of subduction zone science and geochronology, a variety of specialists attended a virtual workshop about earthquake recurrence on the CSZ hosted by the Geological Survey (US) in February 2021. The workshop, which we discuss below, was part of a series that USGS is holding as the agency works on the next update of the National Seismic Hazard Model, due out in 2023.

    Paleoseismology Proxies

    Cascadia has one of the longest and most spatially complete geologic records of subduction zone earthquakes, stretching back more than 10,000 years along much of the 1,300-kilometer-long margin, yet debate persists over the size and recurrence of great earthquakes [Goldfinger et al., 2012; Atwater et al., 2014]. The uncertainty arises in part because we lack firsthand observations of Cascadia earthquakes. Thus, integrating onshore and offshore proxy records and understanding how different geologic environments record past megathrust ruptures remain important lines of inquiry, as well as major hurdles, in CSZ science. These hurdles are exacerbated by geochronologic data sets that differ in their precision and usefulness in revealing past rupture patches.

    One of the most important things to determine is whether proxy evidence records the CSZ rupturing in individual great events (approximately magnitude 9) or in several smaller, clustered earthquakes (approximately magnitude 8) that occur in succession. A magnitude 9 earthquake releases 30 times the energy of a magnitude 8 event, so the consequences of misinterpreting the available data can result in substantial misunderstanding of the seismic hazard.

    Geologic proxies of megathrust earthquakes are generated by different aspects of the rupture process and can therefore inform us about specific rupture characteristics and hazards. Some of the best proxy records for CSZ earthquakes lie onshore in coastal environments. Coastal wetlands, for example, record sudden and lasting land-level changes in their stratigraphy and paleoecology when earthquakes cause the wetlands’ surfaces to drop into the tidal range (Figure 1) [Atwater et al., 2015]. The amount of elevation change that occurs during a quake, called “coseismic deformation,” can vary along the coast during a single event because of changes in the magnitude, extent, and style of slip along the fault [e.g., Wirth and Frankel, 2019]. Thus, such records can reveal consistency or heterogeneity in slip during past earthquakes.

    Tsunami deposits onshore are also important proxies for understanding coseismic slip distribution. Tsunamis are generated by sudden seafloor deformation and are typically indicative of shallow slip, near the subduction zone trench (Figure 1) [Melgar et al., 2016]. The inland extent of tsunami deposits, and their distribution north and south along the subduction zone, can be used to identify places where an earthquake caused a lot of seafloor deformation and can tell generally how much displacement was required to create the tsunami wave.

    Offshore, seafloor sediment cores show coarse layers of debris flows called turbidites that can also serve as great proxies for earthquake timing and ground motion characteristics. Coseismic turbidites result when earthquake shaking causes unstable, steep, submarine canyon walls to fail, creating coarse, turbulent sediment flows. These flows eventually settle on the ocean floor and are dated using radiocarbon measurements of detrital organic-rich material.

    Geochronologic Investigations

    3
    Fig. 2. These graphs show the age range over which different geochronometers are useful (top), the average record length in Cascadia for different environments (middle), and the average uncertainty for different methods (bottom). Marine sediment cores have the capacity for the longest records, but age controls from detrital material in turbidites have the largest age uncertainties. Radiocarbon (^14C) ages from bracketing in-growth position plants and trees (wiggle matching) have much smaller uncertainties (tens of years) but are not preserved in coastal environments for as long. To optimize the potential range of dendrochronological geochronometers, the reference chronology of coastal tree species must be extended further back in time. The range limit (black arrow) of these geochronometers could thus be extended with improved reference chronologies.

    To be useful, proxies must be datable. Scientists primarily use radiocarbon dating to put past earthquakes into temporal context. Correlations in onshore and offshore data sets have been used to infer the occurrence of up to 20 approximately magnitude 9 earthquakes on the CSZ over the past 11,000 years [Goldfinger et al., 2012], although uncertainty in the ages of these events ranges from tens to hundreds of years (Figure 2). These large age uncertainties allow for varying interpretations of the geologic record: Multiple magnitude 8 or magnitude 7 earthquakes that occur over a short period of time (years to decades) could be misidentified as a single huge earthquake. It’s even possible that the most thoroughly examined CSZ earthquake, in 1700, might have comprised a series of smaller earthquakes, not one magnitude 9 event, because the geologic evidence providing precise ages of this event comes from a relatively short stretch of the Cascadia margin [Melgar, 2021].

    By far, the best geochronologic age constraints for CSZ earthquakes come from tree ring, or dendrochronological, analyses of well-preserved wood samples [e.g., Yamaguchi et al., 1997], which can provide annual and even seasonal precision (Figure 2). Part of how scientists arrived at the 26 January date for the 1700 quake was by using dendrochronological dating of coastal forests in southwestern Washington that were killed rapidly by coseismic saltwater submergence. Some of the dead western red cedar trees in these “ghost forests” are preserved with their bark intact; thus, they record the last year of their growth. By cross dating the dead trees’ annual growth rings with those in a multicentennial reference chronology derived from nearby living trees, it is evident that the trees died after the 1699 growing season.

    The ghost forest, however, confirms only that coseismic submergence in 1700 occurred along the 90 kilometers of the roughly 1,300-kilometer-long Cascadia margin where these western red cedars are found. The trees alone do not confirm that the entire CSZ fault ruptured in a single big one.

    Meanwhile, older CSZ events have not been dated with such high accuracy, in part because coseismically killed trees are not ubiquitously distributed and well preserved along the coastline and because there are no millennial-length, species-specific reference chronologies with which to cross date older preserved trees (Figure 2).

    Advances in Dating

    At the Cascadia Recurrence Workshop earlier this year, researchers presented recent advances and discussed future directions in paleoseismic dating methods. For example, by taking annual radiocarbon measurements from trees killed during coseismic coastal deformation, we can detect dated global atmospheric radiocarbon excursions in these trees, such as the substantial jump in atmospheric radiocarbon between the years 774 and 775 [Miyake et al., 2012]. This method allows us to correlate precise dates from other ghost forests along the Cascadian coast from the time of the 1700 event and to date past megathrust earthquakes older than the 1700 quake without needing millennial-scale reference chronologies [e.g., Pearl et al., 2020]. Such reference chronologies, which were previously required for annual age precision, are time- and labor-intensive to develop. With this method, new data collections from coastal forests that perished in or survived through CSZ earthquakes can now give near-annual dates for both inundations and ecosystem transitions.

    4
    Numerous tree rings are evident in this cross section from a subfossil western red cedar from coastal Washington. Patterns in ring widths give clues about when the tree died. Credit: Jessie K. Pearl.

    Although there are many opportunities to pursue with dendrochronology, such as dating trees at previously unstudied sites and trees killed by older events, we must supplement this approach with other novel geochronological methods to fill critical data gaps where trees are not preserved. Careful sampling and interpretation of age results from radiocarbon-dated material other than trees can also provide tight age constraints for tsunami and coastal submergence events.

    For example, researchers collected soil horizons below (predating) and overlying (postdating) a tsunami deposit in Discovery Bay, Wash., and then radiocarbon dated leaf bases of Triglochin maritima, a type of arrowgrass that grows in brackish and freshwater marsh environments. The tsunami deposits, bracketed by well-dated pretsunami and posttsunami soil horizons, revealed a tsunamigenic CSZ rupture that occurred about 600 years ago on the northern CSZ, perhaps offshore Washington State and Vancouver Island [Garrison-Laney and Miller, 2017].

    Multiple bracketing ages can dramatically reduce uncertainty that plagues most other dated horizons, especially those whose ages are based on single dates from detrital organic material (Figure 2). Although the age uncertainty of the 600-year-old earthquake from horizons at Discovery Bay is still on the order of several decades, the improved precision is enough to conclusively distinguish the event from other earthquakes dated along the margin.

    Further advancements in radiocarbon dating continue to provide important updates for dating coseismic evidence from offshore records. Marine turbidites do not often contain materials that provide accurate age estimates, but they are a critically important paleoseismic proxy [Howarth et al., 2021]. Turbidite radiocarbon ages rely on correcting for both global and local marine reservoir ages, which are caused by the radiocarbon “memory” of seawater. Global marine reservoir age corrections are systematically updated by experts as we learn more about past climates and their influences on the global marine radiocarbon reservoir [Heaton et al., 2020]. However, samples used to calibrate the local marine reservoir corrections in the Pacific Northwest, which apply only to nearby sites, are unfortunately not well distributed along the CSZ coastline, and little is known about temporal variations in the local correction, leading to larger uncertainty in event ages.

    These local corrections could be improved by collecting more sampled material that fills spatial gaps and goes back further in time. At the workshop, researchers presented the exciting development that they were in the process of collecting annual radiocarbon measurements from Pacific geoduck clam shells off the Cascadian coastline to improve local marine reservoir knowledge. Geoducks can live more than 100 years and have annual growth rings that are sensitive to local climate and can therefore be cross dated to the exact year. Thus, a chronology of local climatic variation and marine radiocarbon abundance can be constructed using living and deceased specimens. Annual measurements of radiocarbon derived from marine bivalves, like the geoduck, offer new avenues to generate local marine reservoir corrections and improve age estimates for coseismic turbidity flows.

    Putting It All Together

    An imminent magnitude 9 megathrust earthquake on the CSZ poses one of the greatest natural hazards in North America and motivates diverse research across the Earth sciences. Continued development of multiple geochronologic approaches will help us to better constrain the timing of past CSZ earthquakes. And integrating earthquake age estimates with the understanding of rupture characteristics inferred from geologic evidence will help us to identify natural variability in past earthquakes and a range of possible future earthquake hazard scenarios.

    Useful geochronologic approaches include using optically stimulated luminescence to date tsunami sand deposits (Figure 1) and determining landslide age estimates on the basis of remotely sensed land roughness [e.g., LaHusen et al., 2020]. Of particular value will be focuses on improving high-precision radiocarbon and dendrochronological dating of CSZ earthquakes, paired with precise estimates of subsidence magnitude, tsunami inundation from hydrologic modeling, inferred ground motion characteristics from sedimentological variations in turbidity deposits, and evidence of ground failure in subaerial, lake, and marine settings. Together, such lines of evidence will lead to better correlation of geologic records with specific earthquake rupture characteristics.

    Ultimately, characterizing the recurrence of major earthquakes on the CSZ megathrust—which have the potential to drastically affect millions of lives across the region—hinges on the advancement and the integration of diverse geochronologic and geologic records.

    References:

    Atwater, B. F., et al. (2014), Rethinking turbidite paleoseismology along the Cascadia subduction zone, Geology, 42(9), 827–830, https://doi.org/10.1130/G35902.1.

    Atwater, B. F., et al. (2015), The Orphan Tsunami, 2nd ed., U.S. Geol. Surv., Reston, Va.

    Garrison-Laney, C., and I. Miller (2017), Tsunamis in the Salish Sea: Recurrence, sources, hazards, in From the Puget Lowland to East of the Cascade Range: Geologic Excursions in the Pacific Northwest, GSA Field Guide, vol. 49, pp. 67–78, Geol. Soc. of Am., Boulder, Colo. https://doi.org/10.1130/2017.0049(04).

    Goldfinger, C., et al. (2012), Turbidite event history — Methods and implications for Holocene paleoseismicity of the Cascadia Subduction Zone, U.S. Geol. Surv. Prof. Pap., 1661-F, https://doi.org/10.3133/pp1661F.

    Heaton, T. J., et al. (2020), Marine20—The marine radiocarbon age calibration curve (0–55,000 cal BP), Radiocarbon, 62(4), 779–820, https://doi.org/10.1017/RDC.2020.68.

    Howarth, J. D., et al. (2021), Calibrating the marine turbidite palaeoseismometer using the 2016 Kaikōura earthquake, Nat. Geosci., 14(3), 161–167, https://doi.org/10.1038/s41561-021-00692-6.

    LaHusen, S. R., et al. (2020), Rainfall triggers more deep-seated landslides than Cascadia earthquakes in the Oregon Coast Range, USA, Sci. Adv., 6(38), eaba6790, https://doi.org/10.1126/sciadv.aba6790.

    Melgar, D. (2021), Was the January 26th, 1700 Cascadia earthquake part of an event sequence?, EarthArXiv, https://doi.org/10.31223/X5XG78.

    Melgar, D., et al. (2016), Kinematic rupture scenarios and synthetic displacement data: An example application to the Cascadia subduction zone, J. Geophys. Res. Solid Earth, 121, 6,658–6,674, https://doi.org/10.1002/2016JB013314.

    Miyake, F., et al. (2012), A signature of cosmic-ray increase in AD 774–775 from tree rings in Japan, Nature, 486(7402), 240–242, https://doi.org/10.1038/nature11123.

    Pearl, J. K., et al. (2020), A late Holocene subfossil Atlantic white cedar tree-ring chronology from the northeastern United States, Quat. Sci. Rev., 228, 106104, https://doi.org/10.1016/j.quascirev.2019.106104.

    Wirth, E. A., and A. D. Frankel (2019), Impact of down-dip rupture limit and high-stress drop subevents on coseismic land-level change during Cascadia Megathrust earthquakes, Bull. Seismol. Soc. Am., 109(6), 2,187–2,197, https://doi.org/10.1785/0120190043.

    Yamaguchi, D. K., et al. (1997), Tree-ring dating the 1700 Cascadia earthquake, Nature, 389(6654), 922–923, https://doi.org/10.1038/40048.

    See the full article here .

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