From temblor : “Undersea telecom cables detect ocean earthquakes”

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From temblor

April 20, 2021
Lauren Milideo, Ph.D.

Undersea telecom cables detect ocean earthquakes
Posted on April 20, 2021 by Temblor

Researchers used throwaway data from telecom companies to turn submarine telecommunications cables into deep-sea earthquake sensors.

By Lauren Milideo, Ph.D., science writer, (@lwritesscience)

Earthquakes on land often rattle a wide array of seismic sensors, giving researchers plenty of data to analyze. Using these data, seismologists gain a better understanding of how earthquakes occur and where they are more likely to strike in the future. Unfortunately, most of the planet is covered by water and very few seismic sensors monitor the vast oceans. Now, a new study [Science] explores whether underwater telecommunications cables can serve as stand-in sensors and monitor immense spans of Earth’s surface.

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Over 70% of Earth’s surface is covered in water, where seismic monitoring equipment is rare. Credit: jack atkinson, Unsplash.

A fresh approach

The idea of using fiber-optic telecommunications cables to sense earthquakes is not new. Researchers have previously used so-called “dark fibers” — fibers not being actively used within a cable — on land to detect seismic waves and on a limited basis underwater. But until now, research utilizing submarine cables has taken place only on short bits of cable because dark fibers are so rare underwater, says Zhongwen Zhan, a seismologist at CalTech’s Seismological Laboratory. These cables are too expensive to have a large number of dark fibers available for other use. This limits the area over which cables can be used to detect earthquakes.

Zhan and a team of researchers sought a different way to use optical-fiber cables to seismically monitor the oceans. Light waves used to transmit data long distances in cables travel in two perpendicular planes, allowing telecom companies to send a large amount of information at once, notes Zhan. The angle between the waves can change if the light signal is perturbed along its journey from one end of the cable to the other. Telecom companies monitor the information at the receiving end of the cables, says Zhan, to ensure that the signal received matches the signal sent and the two perpendicular signals have not interfered with each other along the way. Telecom companies have no other use for this information after this confirmation. The team realized this unused data may have other applications, Zhan says.

Google’s submarine cable detects quakes

The team turned to Google’s 6,525-mile-long (10,500-kilometer) Curie cable, which runs between Los Angeles, California and Valparaiso, Chile. This cable traverses underwater faults and a seismically active zone in the Pacific Ocean. The steady conditions on the seafloor — with few temperature fluctuations or other vibrations common on land — should cause little disruption in the signal traveling through submarine cables. Yet perturbations were still evident in the arriving signals, notes Zhan. The team found that some of these perturbations occurred at the same time as earthquakes detected by more traditional seismological means. The magnitude-7.4 quake that occurred near Oaxaca, Mexico, on June 23, 2020, was one such occurrence.

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Deploying the Curie cable. Credit: Google Cloud.

“The cool part about this research is that they don’t rely on installing extra instrumentation on cables that are not being used,” says University of Hamburg [Universität Hamburg](DE) Institute of Geophysics professor and seismologist Céline Hadziioannou.

Because the recorded signal perturbation is integrated along the entire cable length, it is not currently possible to know exactly where along the cable a quake occurred using this type of sensing, says Hadziioannou. The researchers describe the potential use of signal perturbation information from several cables at once to determine a quake’s location. Hadziioannou says that “the approach is still very promising and could be quite powerful for future applications of early detection of the fact that there has been a remote earthquake.” Such information is useful, she says. If a large quake is detected along an undersea cable, existing earthquake early warning systems could be triggered before the seismic waves approach land.

“Many of the bigger earthquakes are happening offshore,” Zhan says. “If you only have stations on land, then you are only looking at them from one side and you are really getting very limited understanding of those earthquakes.” He says that with the tremendous distance between these ocean quakes’ origins and land-based sensors, quick warnings of these quakes are not possible, as they would be if a sensor were located closer to the earthquakes.

Another potential application of this method is tsunami warnings, but this is not yet certain. The researchers did detect ocean waves during their study period, Zhan says. “(A) tsunami is one kind of ocean wave, so we are hopeful that maybe one day it will work for detecting tsunamis,” he notes. No major tsunamis occurred during their nine months of observation, so the team does not yet know if submarine cables can detect tsunamis.

Monitoring the vast oceans

The research holds promise in expanding how seismologists are able to view and learn about these quakes happening so far from traditional seismic sensing networks. “This [submarine] network is already there,” says Zhan – a total of over 1.2 million kilometers, according to CNN. Using even a small percentage of these cables for geophysical research would greatly expand the seismic sensing coverage of Earth’s surface, Zhan notes.

References

Zhan, Z., M. Cantono, V. Kamalov, A. Mecozzi, R. Muller, S. Yin & J.C. Castellanos (2021). Optical Polarization-Based Seismic and Water Wave Sensing on Transoceanic Cables. Science. https://doi.org/10.1126/science.abe6648

See the full article here .


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Please help promote STEM in your local schools.

Stem Education Coalition

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Earthquake Alert

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Earthquake Alert

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

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

Get the app in the Google Play store.

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

Meet The Quake-Catcher Network

QCN bloc

Quake-Catcher Network

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The primary project partners include:

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

The Earthquake Threat

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

Part of the Solution

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

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

System Goal

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

Current Status

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

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

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

Authorities

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

For More Information

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

Learn more about EEW Research

ShakeAlert Fact Sheet

ShakeAlert Implementation Plan

QuakeAlertUSA

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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.