From The University of California-Davis (US) : “Evidence for Shared Earthquakes Between San Andreas and San Jacinto Faults”
From The University of California-Davis (US)
December 14, 2021
Andy Fell
A small fault lying between the San Andreas and San Jacinto faults provides evidence for past earthquakes that involved both major faults. Geologists Tom Rockwell (The San Diego State University (US)) and Michael Oskin (The University of California-Davis (US)) work in a trench into the fault. Credit: Alba Rodriguez Padilla/UC Davis).
The San Andreas and San Jacinto faults have ruptured simultaneously at least three times in the past 2,000 years, most recently in 1812, according to a new study by geologists at The University of California-Davis (US), and The San Diego State University (US). The work was published Dec. 7 in the journal Geology.
Large earthquakes involving multiple faults increase the threat of strong ground shaking. However, each of these faults on their own can generate a large-magnitude (7.5 or above) earthquake, said Alba Rodríguez Padilla, a graduate student at UC Davis and first author on the paper.
SAF SJF conjunction
“Typically, we think earthquakes will remain confined to a single fault, especially for “mature” faults such as the San Andreas and the San Jacinto, which are well-established, geometrically simple plate boundary faults,” Rodríguez Padilla said. But researchers previously have shown that it’s theoretically possible for an earthquake to transfer from one fault to another where they come close together at Cajon Pass, north of Los Angeles, she said.
“However, prior to our study, there was no direct physical evidence that these joint ruptures, or shared earthquakes, do in fact occur,” Rodríguez Padilla said.
Between the south end of the San Andreas Fault and the northern end of the San Jacinto lies a small fault, the Lytle Creek Ridge Fault. This fault would slip only when there is an earthquake shared across the two bigger faults.
The Lytle Creek Ridge Fault does not itself do any work during these shared earthquakes, just acting as a passive marker, Rodríguez Padilla said.
20% to 23% of earthquakes shared
To get evidence of potential shared earthquakes, Rodríguez Padilla and colleagues hand-dug a trench 15 meters long and 1.5-3 meters deep into the Lytle Creek Ridge Fault. They identified signs of three earthquake events in the past 2,000 years, based on radiocarbon and pollen dating.
The study involved digging a trench 15 meters long and up to 3 meters deep into the San Gabriel mountains. Credit: Alba Rodríguez Padilla/UC Davis.
That compares to 15 known earthquakes on the San Andreas and 13 on the San Jacinto over the same time. Based on that, the team concluded that 20% to 23% of earthquakes on these major faults are shared with the other fault.
Next, they simulated the historically recorded earthquakes of 1812 and 1857 to see if these could have been multi-fault earthquakes. Based on the simulations, they discarded the 1857 earthquake and found that the 1812 earthquake was capable of jumping faults.
Additional co-authors on the paper are Professor Michael Oskin and project scientist Irina Delusina, UC Davis Department of Earth and Planetary Sciences; and Thomas Rockwell and Drake Singleton, San Diego State University. Julian Lozos, The California State University-Northridge (US), and Kelian Dascher-Cousineau, The University of California-Santa Cruz (US), helped dig the trench.
The work was supported by the Southern California Earthquake Center, which is funded by The Geological Survey (US) and The National Science Foundation (US).
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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.
Smartphone network spatial distribution (green and red dots) on December 4, 2015
Meet The 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
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
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
GNSS station | Pacific Northwest Geodetic Array, Central Washington University (US)
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See the full article here .
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Please help promote STEM in your local schools.
The University of California-Davis (US) is a public land-grant research university near Davis, California. Named a Public Ivy, it is the northernmost of the ten campuses of The University of California (US) system. The institution was first founded as an agricultural branch of the system in 1905 and became the seventh campus of the University of California in 1959.
The university is classified among “R1: Doctoral Universities – Very high research activity”. The University of California-Davis faculty includes 23 members of The National Academy of Sciences, 30 members of The American Academy of Arts and Sciences (US), 17 members of the American Law Institute, 14 members of the Institute of Medicine, and 14 members of the National Academy of Engineering. Among other honors that university faculty, alumni, and researchers have won are two Nobel Prizes, a Presidential Medal of Freedom, three Pulitzer Prizes, three MacArthur Fellowships, and a National Medal of Science.
Founded as a primarily agricultural campus, the university has expanded over the past century to include graduate and professional programs in medicine (which includes the University of California-Davis Medical Center), law, veterinary medicine, education, nursing, and business management, in addition to 90 research programs offered by University of California-Davis Graduate Studies. The University of California-Davis School of Veterinary Medicine is the largest veterinary school in the United States and has been ranked first in the world for five consecutive years (2015–19). University of California-Davis also offers certificates and courses, including online classes, for adults and non-traditional learners through its Division of Continuing and Professional Education.
The UC Davis Aggies athletic teams compete in NCAA Division I, primarily as members of the Big West Conference with additional sports in the Big Sky Conference (football only) and the Mountain Pacific Sports Federation.
Seventh UC campus
In 1959, the campus was designated by the Regents of the University of California as the seventh general campus in the University of California system.
University of California-Davis’s Graduate Division was established in 1961, followed by the creation of the College of Engineering in 1962. The law school opened for classes in fall 1966, and the School of Medicine began instruction in fall 1968. In a period of increasing activism, a Native American studies program was started in 1969, one of the first at a major university; it was later developed into a full department within the university.
Graduate Studies
The University of California-Davis Graduate Programs of Study consist of over 90 post-graduate programs, offering masters and doctoral degrees and post-doctoral courses. The programs educate over 4,000 students from around the world.
UC Davis has the following graduate and professional schools, the most in the entire University of California system:
UC Davis Graduate Studies
Graduate School of Management
School of Education
School of Law
School of Medicine
School of Veterinary Medicine
Betty Irene Moore School of Nursing
Research
University of California-Davis is one of 62 members in The Association of American Universities (US), an organization of leading research universities devoted to maintaining a strong system of academic research and education.
Research centers and laboratories
The campus supports a number of research centers and laboratories including:
Advanced Highway Maintenance Construction Technology Research Laboratory
BGI at UC Davis Joint Genome Center (in planning process)
Bodega Marine Reserve
C-STEM Center
CalEPR Center
California Animal Health and Food Safety Laboratory System
California International Law Center
California National Primate Research Center
California Raptor Center
Center for Health and the Environment
Center for Mind and Brain
Center for Poverty Research
Center for Regional Change
Center for the Study of Human Rights in the Americas
Center for Visual Sciences
Contained Research Facility
Crocker Nuclear Laboratory
Davis Millimeter Wave Research Center (A joint effort of Agilent Technologies Inc. and UC Davis) (in planning process)
Information Center for the Environment
John Muir Institute of the Environment (the largest research unit at UC Davis, spanning all Colleges and Professional Schools)
McLaughlin Natural Reserve
MIND Institute
Plug-in Hybrid Electric Vehicle Research Center
Quail Ridge Reserve
Stebbins Cold Canyon Reserve
Tahoe Environmental Research Center (TERC) (a collaborative effort with Sierra Nevada University)
UC Center Sacramento
UC Davis Nuclear Magnetic Resonance Facility
University of California Pavement Research Center
University of California Solar Energy Center (UC Solar)
Energy Efficiency Center (the very first university run energy efficiency center in the Nation).
Western Institute for Food Safety and Security
The Crocker Nuclear Laboratory on campus has had a nuclear accelerator since 1966. The laboratory is used by scientists and engineers from private industry, universities and government to research topics including nuclear physics, applied solid state physics, radiation effects, air quality, planetary geology and cosmogenics. University of California-Davis is the only University of California campus, besides The University of California-Berkeley (US), that has a nuclear laboratory.
Agilent Technologies will also work with the university in establishing a Davis Millimeter Wave Research Center to conduct research into millimeter wave and THz systems.
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