From U Washington: “Hacking a pressure sensor to track gradual motion along marine faults”

University of Washington

September 21, 2017
Hannah Hickey

Deep below the ocean’s surface, shielded from satellite signals, the gradual movement of the seafloor — including along faults that can unleash deadly earthquakes and tsunamis — goes largely undetected. As a result, we know distressingly little about motion along the fault that lies just off the Pacific Northwest coast.

University of Washington oceanographers are working with a local company to develop a simple new technique that could track seafloor movement in earthquake-prone coastal areas. Researchers began testing the approach this summer in central California, and they plan to present initial results in December at the American Geophysical Union’s annual meeting in New Orleans.

The modified pressure sensor is now being tested at the bottom of Monterey Bay.MBARI/University of Washington

Their approach uses existing water-pressure sensors to cheaply measure gradual swelling of the seafloor over months to years. If successful, the innovative hack could provide new insight into motion along the Cascadia Subduction Zone and similar faults off Mexico, Chile and Japan. The data could provide clues about what types of earthquakes and tsunamis each fault can generate, where and how often.

The concept began with a workshop in 2012 that brought together Jerry Paros, the founder of Bellevue-based Paroscientific, Inc., with UW geoscientists. Paros’ company manufactures sensors used to measure pressure at the bottom of the ocean with high precision, which are used by the National Oceanographic and Atmospheric Administration for its tsunami sensors.

The Paroscientific sensor’s crystal inside this instrument can measure crushing pressures on the seafloor. University of Washington researchers altered the sensor to monitor seismic creep by calibrating its measurements against the pressure inside the silver titanium case.University of Washington

But an engineering quirk prevents the sensors from measuring the gradual ground motions that build up pressure along earthquake faults. The instruments can measure seafloor pressure, or the weight of water above the sensor, to an extremely precise fraction of a millimeter. But the readings lose accuracy over time, and the error is proportional to the quantity measured. On the ocean floor, where pressures are tens to hundreds of times that on the surface, the readings can change by 10 centimeters (3 inches) per year. In between major earthquakes, this is much more than the seafloor might shift up or down due to tectonic forces.

“If you want to measure how the seafloor is moving, you don’t want your reading to change by a larger value than the thing that you’re measuring,” said Dana Manalang, an engineer at the UW’s Applied Physics Laboratory who is working on the project.

Paros proposed an idea that would instead calibrate the pressure sensor against the air pressure inside the metal case that houses the instrument, which is roughly one atmosphere. This would allow existing pressure sensors to autonomously track small bulges and slumps on the seafloor.

This deep-sea robot, the ROV Ventana operated by Monterey Bay Aquarium Research Institute, in June attached the instrument (lower right) to the Internet-connected observatory at the bottom of Monterey Bay.MBARI/University of Washington

Last year engineers at the UW Applied Physics Laboratory modified an existing Paros pressure sensor. The sensitive quartz crystal that measures the seafloor pressure can now be connected to measure pressure inside its titanium instrument case, with a known pressure and another barometer to check the value. The prototype instrument was attached in mid-June to the Monterey Accelerated Research System, a cabled seafloor observatory that lets researchers communicate directly with the instrument.

“That chunk of seafloor actually does not move much. We’re looking for a null result,” Manalang said. “If successful, the next step would be to deploy similar instruments in some more geologically active areas.”

Those areas include the Cascadia Subduction Zone, the fault that could unleash the Really Big One at any time on the Pacific Northwest.

http://www.zerohedge.com/news/2016-05-30/fema-preparing-magnitude-90-cascadia-subduction-zone-earthquake-tsunami

Geologists studying the small rise and fall of this section of seafloor, around 1 centimeter per year, have instead been forced to develop complicated workarounds.

“We are trying to find a pattern of which areas are going up and which areas are going down, and how quickly, which can potentially tell us where the subduction zone fault is locked,” said William Wilcock, a UW oceanography professor who holds the Paros endowed chair. “But we can’t yet do that with a conventional pressure sensor.”

Wilcock and seismologists at Scripps Institution of Oceanography have been monitoring seafloor movement off central Oregon, where the Cascadia Fault displays behavior that suggests it may gradually slip, releasing strain along that section of the fault. Once a year, the partners go to sea with a research ship, deep-sea robot and specialized equipment to calibrate six seafloor pressure sensors. By monitoring exactly how the seafloor has moved in this way from one summer to the next, they can compare sections of the fault and learn which zones are fully locked, building up potentially dangerous energy, and which aren’t.

“The approach we are using appears to work, but it’s expensive, and you can’t do it very often,” Wilcock said.

If Paros’ modified sensors can do the job, future work might place a network of them along Cascadia or other subduction zones, in which a seafloor plate plunges beneath a continental plate. Measuring motion along different parts of these faults might answer longstanding questions about how and where a fault ruptures.

From her Seattle office, Manalang now communicates with the prototype sensor in Monterey and flips the crystal about once each weekday to recalibrate it against the instrument housing pressure. She will flip it less often as the test continues, while remotely monitoring the change in pressure readings.

“We’re still close to the starting line on this one, and have some initial, really promising results,” Manalang said. Observations so far show that the shift in measurements is predictable, and similar at both ends of the instrument’s range. “We’re at the very beginning of what we hope is a fairly long-term test,” she said.

If the method proves reliable, future pressure sensors could be programmed to pivot periodically on their own and gather observations over months or years. Precise long-term measurements of water pressure could not only help seismologists, but also researchers who study how sea level changes over decades.

“If you can make very accurate observations, and routinely, it would interest both the people studying what’s happening beneath and what’s happening above,” Wilcock said. “These data would open up a whole bunch of new studies.”

The research is funded by Jerry Paros and the University of Washington.

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.

So what defines us — the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

Advertisements

From temblor: “M=7.1 earthquake collapses buildings in Mexico City on the 32nd anniversary of a deadly M=8.0 quake”

temblor

September 19, 2017
David Jacobson, Temblor
Professor Shinji Toda,
IRIDeS, Tohoku University, Japan

This Temblor map shows the location of today’s M=7.1 earthquake just south of the country’s capital, Mexico City.

At 1:14 p.m. local time, a M=7.1 earthquake struck just south of Puebla, Mexico, and 120 km from Mexico City, where almost 9 million people reside. From the initial USGS ShakeMap, severe shaking was felt close to the epicenter, while in Mexico City, they would have experienced moderate to strong shaking, enough to cause significant damage. Ironically, this earthquake comes on the 32nd anniversary of a deadly M=8.0 earthquake in Mexico City which killed over 5,000 people and caused billions in damage. Furthermore, as an observance to the anniversary, several buildings held earthquake drills earlier in the day. Unlike today’s quake, which struck southeast of the city, that earthquake was centered over 350 km to the southwest of the capital.

Based on reports and photos, we know that at least 42 people are confirmed to have died, and buildings have collapsed in Mexico City. The USGS PAGER system estimates that economic losses could reach $1 billion, with up to 1,000 fatalities. This deadly quake comes less than 2 weeks after a M=8.1 earthquake shook the Chiapas region to the southeast. While the magnitude of that quake was significantly larger than today’s, shaking in Mexico City was greater today, given the proximity of the epicenter to the city.

Today’s M=7.1 earthquake south of Mexico City resulted in significant damage throughout the city. (Photo from: Ronaldo Schemidt/Agence France-Presse — Getty Images)

Despite the fact that just offshore of Mexico is the Middle America Trench, where the Cocos plate subducts beneath the North American plate at a rate of approximately 76 mm/yr, today’s event, like the earthquake on Sept 7, was extensional in nature. Depending on the subduction model used, today’s earthquake could have either been within the subducting Cocos plate (Franco et al., 2005), or the overriding North American plate (Hayes et al., 2012). This difference is a matter of how much the dip of the subducting slab shallows. Professor Shinji Toda at IRIDeS, Tohoku University, Japan, says that while intraslab earthquakes are typically not as destructive as subduction zone events, their sources are totally invisible and are thus extremely unpredictable. Additionally, he suggests that while inland Mexico is dominated by subduction megathrust events and onshore active faults, a flattened slab layer could be a third source of large earthquakes.

This figure, which has been modified from Franco et al., 2005 shows the location of the two large recent earthquake in Mexico. Additionally, it shows the rupture areas of other large historic earthquakes in the country. Lastly, this figure highlights how both of the large earthquakes in the last two weeks were likely intraplate events within the subducting Cocos Plate.

From the focal mechanism and location of today’s event, it may have struck within the Trans-Mexican Volcanic Belt. While this chain of active volcanoes is the product of subduction at the Middle America Trench, there is regional extension. Throughout this volcanic belt, which runs across central Mexico, there are pronounced east-west-oriented extensional faults. Based on historical earthquakes, there is no known subduction zone seismicity below the Trans-Mexican Volcanic Belt (Suter et al., 2001). This means that any earthquake within this zone is likely to be extensional.

From the Global Earthquake Activity Rate (GEAR) model, which is available in Temblor, today’s M=7.1 earthquake just south of Mexico City can be considered surprising. This model uses global strain rates and the last 40 years of seismicity to forecast the likely earthquake magnitude in your lifetime anywhere on earth. From this model, which is shown below, one can see that in the location of today’s event, the likely magnitude is M=6.5-6.75. Having said that, in 1999, a M=7.0 earthquake struck just roughly 100 km to the east. That too was an extensional earthquake likely associated with the Trans-Mexican Volcanic Belt. As more information comes in on this earthquake, we will either update this blog, or post an entirely new one.

This Temblor map shows the Global Earthquake Activity Rate (GEAR) model for much of Mexico as well as the locations of today’s M=7.1 earthquake, and the M=8.1 quake less than two weeks ago. What this map shows is that based on their magnitudes, both of these quakes should be considered relatively surprising.

References [No links]
USGS
European-Mediterranean Seismological Centre
Max Suter, Margarita Lopez Martınez, Odranoel Quintero Legorreta, and Miguel Carrillo Martınez, Quaternary intra-arc extension in the central Trans-Mexican volcanic belt, GSA Bulletin; June 2001; v. 113; no. 6; p. 693–703
Franco et al., Propagation of the 2001-2002 silent earthquake and interplate coupling in the Oaxaca subduction zone, Mexico, Earth Planets and Space · October 2005

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

You can help many citizen scientists in detecting earthquakes and getting the data to emergency services people in affected area.

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

Earthquake country is beautiful and enticing

Almost everything we love about areas like the San Francisco bay area, the California Southland, Salt Lake City against the Wasatch range, Seattle on Puget Sound, and Portland, is brought to us by the faults. The faults have sculpted the ridges and valleys, and down-dropped the bays, and lifted the mountains which draw us to these western U.S. cities. So, we enjoy the fruits of the faults every day. That means we must learn to live with their occasional spoils: large but infrequent earthquakes. Becoming quake resilient is a small price to pay for living in such a great part of the world, and it is achievable at modest cost.

A personal solution to a global problem

Half of the world’s population lives near active faults, but most of us are unaware of this. You can learn if you are at risk and protect your home, land, and family.

Temblor enables everyone in the continental United States, and many parts of the world, to learn their seismic, landslide, tsunami, and flood hazard. We help you determine the best way to reduce the risk to your home with proactive solutions.

Earthquake maps, soil liquefaction, landslide zones, cost of earthquake damage

In our iPhone and Android and web app, Temblor estimates the likelihood of seismic shaking and home damage. We show how the damage and its costs can be decreased by buying or renting a seismically safe home or retrofitting an older home.

Please share Temblor with your friends and family to help them, and everyone, live well in earthquake country.

Temblor is free and ad-free, and is a 2017 recipient of a highly competitive Small Business Innovation Research (‘SBIR’) grant from the U.S. National Science Foundation.

ShakeAlert: Earthquake Early Warning

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 by 2018.

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, depending on the distance to the epicenter of the earthquake. For very large events like those expected on the San Andreas fault zone or the Cascadia subduction zone the warning time could be much longer because the affected area is much larger. ShakeAlert can give enough time to slow and stop 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 by 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” test 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. This “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

From U Aberdeen: “Scientists locate potential magma source in Italian supervolcano”

University of Aberdeen

18 September 2017
Robert Turbyne
robert.turbyne@abdn.ac.uk

Scientists have now pinpointed the location of the hot zone where hot materials rose to feed the caldera during its last period of activity in the 1980s.

Scientists have found the first direct evidence of a so-called ‘hot zone’ feeding a supervolcano in southern Italy that experts say is nearing eruption conditions.

Campi Flegrei is a volcanic caldera to the west of Naples that last erupted centuries ago.

The area has been relatively quiet since the 1980s when the injection of either magma or fluids in the shallower structure of the volcano caused a series of small earthquakes.

Using seismological techniques, scientists have now pinpointed the location of the hot zone where hot materials rose to feed the caldera during this period.

The study was led by Dr Luca De Siena at the University of Aberdeen in conjunction with the INGV Osservatorio Vesuviano, the RISSC lab of the University of Naples, and the University of Texas at Austin. The research provides a benchmark that may help predict how and where future eruptions could strike.

“One question that has puzzled scientists is where magma is located beneath the caldera, and our study provides the first evidence of a hot zone under the city of Pozzuoli that extends into the sea at a depth of 4 km,” Dr De Siena said.

“While this is the most probable location of a small batch of magma, it could also be the heated fluid-filled top of a wider magma chamber, located even deeper.”

Dr De Siena’s study suggests that magma was prevented from rising to the surface in the 1980s by the presence of a 1-2 km-deep rock formation that blocked its path, forcing it to release stress along a lateral route.

While the implications of this are still not fully understood, the relatively low amount of seismic activity in the area since the 1980s suggests that pressure is building within the caldera, making it more dangerous.

“During the last 30 years the behaviour of the volcano has changed, with everything becoming hotter due to fluids permeating the entire caldera,” Dr De Siena explained.

“Whatever produced the activity under Pozzuoli in the 1980s has migrated somewhere else, so the danger doesn’t just lie in the same spot, it could now be much nearer to Naples which is more densely populated.

“This means that the risk from the caldera is no longer just in the centre, but has migrated. Indeed, you can now characterise Campi Flegrei as being like a boiling pot of soup beneath the surface.

“What this means in terms of the scale of any future eruption we cannot say, but there is no doubt that the volcano is becoming more dangerous.

“The big question we have to answer now is if it is a big layer of magma that is rising to the surface, or something less worrying which could find its way to the surface out at sea.”

Dr De Siena’s study – Source and dynamics of volcanic caldera unrest: Campi Flegrei. 1983-84 – is available to view here: https://www.nature.com/articles/s41598-017-08192-7

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

Founded in 1495 by William Elphinstone, Bishop of Aberdeen and Chancellor of Scotland, the University of Aberdeen is Scotland’s third oldest and the UK’s fifth oldest university.

William Elphinstone established King’s College to train doctors, teachers and clergy for the communities of northern Scotland, and lawyers and administrators to serve the Scottish Crown. Much of the King’s College still remains today, as do the traditions which the Bishop began.

King’s College opened with 36 staff and students, and embraced all the known branches of learning: arts, theology, canon and civil law. In 1497 it was first in the English-speaking world to create a chair of medicine. Elphinstone’s college looked outward to Europe and beyond, taking the great European universities of Paris and Bologna as its model.
Uniting the Rivals

In 1593, a second, Post-Reformation University, was founded in the heart of the New Town of Aberdeen by George Keith, fourth Earl Marischal. King’s College and Marischal College were united to form the modern University of Aberdeen in 1860. At first, arts and divinity were taught at King’s and law and medicine at Marischal. A separate science faculty – also at Marischal – was established in 1892. All faculties were opened to women in 1892, and in 1894 the first 20 matriculated female students began their studies. Four women graduated in arts in 1898, and by the following year, women made up a quarter of the faculty.

Into our Sixth Century

Throughout the 20th century Aberdeen has consistently increased student recruitment, which now stands at 14,000. In recent years picturesque and historic Old Aberdeen, home of Bishop Elphinstone’s original foundation, has again become the main campus site.

The University has also invested heavily in medical research, where time and again University staff have demonstrated their skills as world leaders in their field. The Institute of Medical Sciences, completed in 2002, was designed to provide state-of-the-art facilities for medical researchers and their students. This was followed in 2007 by the Health Sciences Building. The Foresterhill campus is now one of Europe’s major biomedical research centres. The Suttie Centre for Teaching and Learning in Healthcare, a £20m healthcare training facility, opened in 2009.

From Eos: “Revising an Innovative Way to Study Cascadia Megaquakes”

AGU

Eos

9.12.17
Sarah Witman

Researchers probe natural environments near subduction zones to decrypt underlying mechanisms of major earthquakes.

FEMA

A diagram of the Cascadia Subduction Zone provided by the Oregon Historical Society.

The Cascadia subduction zone is likely to experience a megathrust earthquake in the next 50 years or so, but a revised technique uses heat data to better understand the physical nature of subduction zones. Credit: NASA/ISS

Along the west coast of North America, the Cascadia subduction zone stretches more than 1,000 kilometers from Vancouver Island to Cape Mendocino, Calif. It produced a magnitude 9 megathrust earthquake about 300 years ago, one of the biggest quakes in world history.

Scientists know that Cascadia will produce another earthquake at some point in the future; the question is how soon. The odds of it happening in the next 50 years are 1 in 3. The Federal Emergency Management Agency projects that Cascadia’s next megathrust earthquake will cause thousands of deaths and injuries and leave millions in need of shelter, food, and water.

To better understand subduction zones, scientists often study the thermal environments of material that has been pushed up onto the surface during past earthquakes. This buildup of material, called an accretionary wedge, might consist of rock, soil, sand, shells, or any other kind of debris. These wedges also sport subtly different average temperatures at various depths, compared to material located off the wedge.

In a recent study, Salmi et al. [Journal of Geophysical Research] examined the thermal environment of the Cascadia subduction zone’s accretionary wedge, which stretches for about 97 kilometers along the coast of the state of Washington. Their goal was to find out more about the physical changes of fluids and solids within the wedge in the hopes that the knowledge can help them better anticipate future earthquakes.

Using data collected on a cruise by the R/V Marcus G. Langseth, the researchers found significant variations in temperature within this section of the Cascadia subduction zone, as well as signs of gas hydrates (ice-like deposits that form from natural gas at the bottom of the ocean) throughout the region. They also detected that most fluids from the deep move upward through the accretionary wedge instead of through the crust, which is different than in most other subduction zones. This change in fluid pathway prevents the plate from cooling and reduces the area where an earthquake might rupture along the two plates: completely within the accretionary wedge, rather than under the continental plate.

This is the first study to concentrate on the southern Washington margin alone, rather than the subduction zone as a whole, revealing the influence of fluid distribution on local, small-scale temperature variability. This insight opens the door to further research into how local temperature variability might interact with other factors, like stress or fault roughness, to affect earthquake hazards. Overall, this study provides a revised method for probing the thermal environment of an accretionary wedge, a crucial link to the cause of ruptures in Earth’s crust that can lead to earthquakes and tsunamis.

By understanding these mechanisms more fully, scientists can tell us more about how to prepare for the smallest of tremors and the largest of megaquakes. (Journal of Geophysical Research: Solid Earth, https://doi.org/10.1002/2016JB013839, 2017)

See the full article here .

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.

From temblor: “M=8 earthquake strikes offshore Mexico”

temblor

September 7, 2017
David Jacobson

At 11:49 p.m. local time, a M=8.0 earthquake struck offshore Mexico at a depth of 69 km according to the USGS (The European-Mediterranean Seismological Centre assigned it a depth of 61 km). In the six hours following the mainshock, there have been 28 M=4.3+ aftershocks, which have caused further panic in Mexico. This quake occurred approximately 80 km offshore, and triggered a tsunami warning for Mexico, Guatemala, Panama, El Salvador, Costa Rica, Nicaragua, Honduras and Ecuador. As of 6 a.m. Pacific time, the largest waves recorded were 2.3 feet.

This Temblor map shows the location of tonight’s M=8.0 earthquake off the coast of Mexico. According to the USGS, the quake struck at a depth of 69 km, and registered violent shaking near the epicenter.

This massive earthquake took place on the Middle America Trench, where the Cocos Plate subducts beneath the North American Plate at a rate of roughly 80 mm/yr. Because of the magnitude of this quake, it was felt as far away as Mexico City and Guatemala City, which combined, are home to over 10 million people. Based on the USGS ShakeMap, and regional populations, over 40 million people would have felt this earthquake at varying degrees of severity. According to the New York Times, panicked residents in Mexico City rushed into the streets as their buildings swayed. Even though USGS PAGER system forecasts that fatalities will be between 1,000 and 10,000, so far, there are only 15 confirmed. However, because this earthquake happened at night, this number is sure to rise. The USGS PAGER system also predicts that economic losses will likely total more than $1 billion. Initial reports suggest that there are several collapsed buildings close to the epicenter.

Despite the fact that this earthquake occurred near the Middle America Trench, a compressional environment, the initial (as of 11 p.m. Pacific Time) USGS focal mechanism suggests that this quake was due to extensional motion. Based on the depth of the quake (69 km) it struck below the subduction zone, meaning the extensional nature could be due to a changing dip angle in the subducting slab. However, it is also possible that in the coming hours, new data will arrive, and if it does, we will be sure to update this post.

Based on the Global Earthquake Activity Rate (GEAR) model, which is available in Temblor, this M=8.0 earthquake can be considered relatively surprising. This model uses global strain rates and the last 40 years of seismicity to forecast the likely earthquake magnitude in your lifetime anywhere on earth. From the figure below, one can see that in this area off the coast of Mexico, the likely magnitude in your lifetime is 7.25. This highlights the unpredictability of earthquakes, and that in areas susceptible to large quakes, people need to be aware of the risks and protect themselves in any ways possible.

his Temblor map shows the Global Earthquake Activity Rate (GEAR) model for the area around tonight’s M=8.0 earthquake. This model uses global strain rates and the last 40 years of seismicity to forecast the likely earthquake magnitude in your lifetime anywhere on earth. Based on this model, tonight’s M=8.0 earthquake can be considered surprising as the expected magnitude to occur in your lifetime in this area is M=7.25.

References [no links]
USGS
EMSC
New York Times
CNN

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

You can help many citizen scientists in detecting earthquakes and getting the data to emergency services people in affected area.

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

Earthquake country is beautiful and enticing

Almost everything we love about areas like the San Francisco bay area, the California Southland, Salt Lake City against the Wasatch range, Seattle on Puget Sound, and Portland, is brought to us by the faults. The faults have sculpted the ridges and valleys, and down-dropped the bays, and lifted the mountains which draw us to these western U.S. cities. So, we enjoy the fruits of the faults every day. That means we must learn to live with their occasional spoils: large but infrequent earthquakes. Becoming quake resilient is a small price to pay for living in such a great part of the world, and it is achievable at modest cost.

A personal solution to a global problem

Half of the world’s population lives near active faults, but most of us are unaware of this. You can learn if you are at risk and protect your home, land, and family.

Temblor enables everyone in the continental United States, and many parts of the world, to learn their seismic, landslide, tsunami, and flood hazard. We help you determine the best way to reduce the risk to your home with proactive solutions.

Earthquake maps, soil liquefaction, landslide zones, cost of earthquake damage

In our iPhone and Android and web app, Temblor estimates the likelihood of seismic shaking and home damage. We show how the damage and its costs can be decreased by buying or renting a seismically safe home or retrofitting an older home.

Please share Temblor with your friends and family to help them, and everyone, live well in earthquake country.

Temblor is free and ad-free, and is a 2017 recipient of a highly competitive Small Business Innovation Research (‘SBIR’) grant from the U.S. National Science Foundation.

ShakeAlert: Earthquake Early Warning

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 by 2018.

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, depending on the distance to the epicenter of the earthquake. For very large events like those expected on the San Andreas fault zone or the Cascadia subduction zone the warning time could be much longer because the affected area is much larger. ShakeAlert can give enough time to slow and stop 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 by 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” test 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. This “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

From Eos: “A Closer Look at an Undersea Source of Alaskan Earthquakes”

AGU

Eos

15 August 2017
Daniel S. Brothers
Peter Haeussler
Amy East
Uri ten Brink
Brian Andrews
Peter Dartnell
Nathan Miller
Jared Kluesner

All is calm in southern Alaska’s Lisianski Inlet in this 2015 view from the deck of the R/V Solstice. A systematic survey of the nearby Queen Charlotte–Fairweather Fault, the source of several major earthquakes, has produced valuable information on the fault’s structure and slip mechanisms. Credit: Daniel S. Brothers

During the past century, movement along the Queen Charlotte–Fairweather fault, which lies for most of its length beneath the waters off southeastern Alaska and British Columbia, has generated at least seven earthquakes of magnitude 7 or greater. This includes a magnitude 8.1 earthquake in 1949, the largest ever recorded in Canada.

Other events include a magnitude 7.8 earthquake in 1958 that dislodged a massive landslide above Lituya Bay, Alaska. The earthquake generated a tsunami that sent water 525 meters up the mountainside, a world record run-up [Miller, 1960]. The 2012 magnitude 7.8 Haida Gwaii earthquake, centered on Moresby Island, British Columbia, and the 2013 magnitude 7.5 earthquake near Craig, Alaska [Walton et al., 2015], increased awareness of the potential geologic hazards posed to residents of southeastern Alaska and western British Columbia.

Together, these events highlight the need for a greater understanding of the Queen Charlotte–Fairweather fault and its history.

Yet despite the dramatic effects of this fault’s activity, a near absence of high-resolution marine geophysical and geological data limits scientific understanding of its slip rate, earthquake recurrence interval, paleoseismic history, and rupture dynamics.

The U.S. Geological Survey (USGS) has now completed a systematic examination of the tectonic geomorphology along a 500-kilometer-long undersea section of the Queen Charlotte–Fairweather fault that offers new insights into activity at this strike-slip boundary, where the North American and Pacific plates slide horizontally past each other.

Fig. 1. Recent geophysical surveys provided high-resolution seafloor depth data for the northernmost undersea portion of the Queen Charlotte–Fairweather fault (area outlined in red). The colored seafloor relief represents multibeam echo sounder data acquired along the continental shelf and slope in 2015 and 2016; the gray seafloor relief in deeper water west of the fault was acquired by the University of New Hampshire in 2005. Black boxes are locations of depth imagery shown in Figures 2a–2d. Purple lines represent high-resolution seismic reflection profiles that were acquired in 2016 aboard the R/V Norseman. One such profile (green line) is shown in Figure 3. AMT represents the Alaska-Aleutian megathrust, and ME indicates Mount Edgecumbe.

A Complicated Boundary

The Queen Charlotte–Fairweather fault system and its better known counterpart, the San Andreas fault (which is highly visible on land in California), form the boundary between the North American and Pacific tectonic plates. The Queen Charlotte–Fairweather fault system defines this plate boundary for a distance of more than 1,200 kilometers, from Yakutat, Alaska, to the Queen Charlotte Triple Junction, a confluence of three faults west of British Columbia (Figure 1). Within this system, the Queen Charlotte fault represents the underwater section and is widely recognized as one of the world’s most seismically active continent-ocean transform faults [Plafker et al., 1978; Bruns and Carlson, 1987; Nishenko and Jacob, 1990; Walton et al., 2015].

The northern part of the boundary between the North American and Pacific plates is complicated by the collision of the Yakutat terrane, a block of crustal material surrounded by faults, with southern Alaska. In this region, the Pacific Plate begins to subduct, or plunge beneath, the North American Plate along a boundary known as the Alaska-Aleutian megathrust.

The Fairweather fault is the only stretch of the fault system accessible by land. To the south of Icy Point, the Fairweather fault runs offshore, becoming the Queen Charlotte fault, which extends about 900 kilometers southward along the continental slope.

Earlier studies estimated a slip rate of 41 to 58 millimeters per year on the Fairweather fault [Plafker et al., 1978; Bruns and Carlson, 1987; Elliot et al., 2010], but few direct observations of horizontal seafloor displacement existed [Bruns and Carlson, 1987] because of the absence of high-resolution seabed data.

Geophysical Surveys

In 2015, our team conducted two marine geophysical surveys, one aboard the research vessel R/V Solstice and a second on R/V Alaskan Gyre. We collected high-resolution seafloor depth data using multibeam sonar along the northernmost section of the fault. We also used a chirp subbottom profiler, which returns detailed images down to 50 meters beneath the seafloor.

The Queen Charlotte–Fairweather fault lies off the coast of southeastern Alaska. New imagery of a 400-kilometer-long undersea section of this transform fault provides a striking view of its structure and offers insights into activity at the boundary between the North American and Pacific tectonic plates. This perspective view of depth data acquired during recent surveys of the area shows the fault as it emerges from the Alaskan coast and stretches as a distinct line across the ocean floor. The color spectrum from red to purple represents increasing water depth.

In 2016, two additional cruises (aboard R/V Medeia and R/V Norseman) extended data coverage of the Queen Charlotte–Fairweather fault an additional 325 kilometers southward. We again used multibeam sonar to map the ocean floor and multichannel seismic reflection to image deeper layers of sediment. Most recently, seismic reflection and chirp surveys were completed in July 2017 aboard the R/V Ocean Starr.

In total, during 95 days of seagoing operations, we collected more than 5,000 square kilometers of high-resolution depth data, 9,400 kilometers of high-resolution multichannel seismic reflection profiles, and 500 kilometers of subbottom chirp data.

A Clearer View of the Fault System

Imagery from the surveys shows the fault in pristine detail, cutting straight across the seafloor, with offsetting seabed channels and submerged glacial valleys (Figure 2). The continuous knife-edge character of the fault is evident over the entire 500-kilometer-long survey area. At the same time, we can see several previously unknown features, including a series of subtle bends and steps in the fault that appear to form basins within the fault zone.

Fig. 2. High-resolution depth images at four locations along the Queen Charlotte fault show the morphological features of the fault and the continental slope. Red arrows indicate the relative sense of motion (see Figure 1 for locations).

Because the surveys spanned four sections of the fault that ruptured in significant historical earthquakes, the results provide a unique catalog of geomorphic features commonly associated with active strike-slip faults.

The Fairweather fault bends 20° as it extends southward across the shoreline near Icy Point (Figures 1 and 2a) and then continues southward at a 340° strike along the shelf edge as a single fault trace for another 150 kilometers.

Numerous submarine canyons, gullies, and ridges have been displaced or warped along the fault. Fault valleys parallel to the margin locally separate geomorphically distinct upper and lower sections of the continental slope (Figures 2b and 3). A Pleistocene basaltic-andesitic volcanic edifice exposed at the seabed extends from Mount Edgecumbe to the shelf edge (Figure 2b).

West of southern Baranof Island, the fault takes a series of subtle 3° to 5° right steps and bends that form en echelon pull-apart basins along the shelf edge (Figure 2c). The fault continues southward as a single lineament but exhibits a subtle warp and series of westward steps displacing submarine canyon valleys (Figure 2d) before crossing Noyes Canyon and extending southward into Canadian waters [see, e.g., Barrie et al., 2013].

Fig. 3. A seismic reflection profile acquired in August 2016 highlights the structure and stratigraphy of the continental slope.

Fault Slip Rates

The offset features along the seabed provide important information for reconstructing past fault motion. From the ages of these features we can calculate the average rate of motion along the fault, then estimate the typical recurrence interval for large earthquakes.

For example, the southern margin of the Yakobi Sea Valley has been sliced and translated about 925 meters by the linear, knife-edge fault trace (Figure 2a). Ice likely retreated from the valley about 17,000 years ago. Thus, the slip rate of the Queen Charlotte–Fairweather fault across the Yakobi Sea Valley exceeds 50 millimeters per year: one of the fastest-slipping continent-ocean transform faults in the world [Brothers et al., 2015].

Furthermore, we observe coincidence between the pull-apart basins shown in Figure 2c and the northernmost extent of the 2013 Craig earthquake, implying that changes in fault geometry likely influenced the length of rupture propagation [e.g., Walton et al., 2015].

Future Plans

The USGS, the Geological Survey of Canada, the Sitka Sound Science Center, and the University of Calgary will jointly lead a research cruise in September 2017 to collect sediment cores along the Queen Charlotte–Fairweather fault in Canadian and U.S. territories to constrain the sedimentation history along the margin and date features offset by fault motion.

Overall, this project has shown that the Queen Charlotte–Fairweather fault is an ideal laboratory to examine the tectonic geomorphology of a major strike-slip fault and the associated processes responsible for generating offshore hazards.

Acknowledgments

We thank J. Currie, G. Hatcher, R. Wyland, A. Balster-Gee, P. Hart, J. Conrad, T. O’Brien, A. Nichols, M. Walton, R. Marcuson, and E. Moore of the U.S. Geological Survey (USGS); K. Green of the Alaska Department of Fish and Game; G. Greene of Moss Landing Marine Laboratories; V. Barrie and K. Conway of the Geological Survey of Canada; and the crews of the R/V Solstice, R/V Medeia, R/V Norseman, R/V Ocean Starr, and R/V Alaskan Gyre. We also thank J. Warrick, R. von Huene, J. Watt, and an anonymous reader for helpful reviews. The USGS Coastal and Marine Geology Program funded this study. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. government.

References

Barrie, J. V., K. W. Conway, and P. T. Harris (2013), The Queen Charlotte fault, British Columbia: Seafloor anatomy of a transform fault and its influence on sediment processes, Geo Mar. Lett., 33, 311–318, https://doi.org/10.1007/s00367-013-0333-3.

Brothers, D. S., et al. (2015), High-resolution geophysical constraints on late Pleistocene–Present deformation history, seabed morphology, and slip-rate along the Queen Charlotte-Fairweather fault, offshore southeastern Alaska, Abstract NH23B-1882 presented at 2015 Fall Meeting, AGU, San Francisco, Calif.

Bruns, T. R., and P. R. Carlson (1987), Geology and petroleum potential of the southeast Alaska continental margin, in Geology and Petroleum Potential of the Continental Margin of Western North America and Adjacent Ocean Basins, Beaufort Sea to Baja California, Earth Sci. Ser., vol. 9, edited by D. W. Scholl, A. Grantz, and J. G. Vedder, pp. 269–282, Circum-Pac. Counc. for Energy and Miner. Resour., Houston, Texas.

Elliot, J. L., et al. (2010), Tectonic block motion and glacial isostatic adjustment in southeast Alaska and adjacent Canada constrained by GPS measurements, J. Geophys. Res., 115, B09407, https://doi.org/10.1029/2009JB007139.

Miller, D. J. (1960), Giant waves in Lituya Bay, Alaska, U.S. Geol. Surv. Prof. Pap., 354-C, 51–86, scale 1:50,000.

Nishenko, S. P., and K. H. Jacob (1990), Seismic potential of the Queen Charlotte-Alaska-Aleutian seismic zone, J. Geophys. Res., 95(B3), 2511–2532, https://doi.org/10.1029/JB095iB03p02511.

Plafker, G., et al. (1978), Late Quaternary offsets along the Fairweather fault and crustal plate interactions in southern Alaska, Can. J. Earth Sci., 15(5), 805–816, https://doi.org/10.1139/e78-085.

Walton, M. A. L., et al. (2015), Basement and regional structure along strike of the Queen Charlotte fault in the context of modern and historical earthquake ruptures, Bull. Seismol. Soc. Am., 105, 1090–1105, https://doi.org/10.1785/0120140174.

Author Information

Daniel S. Brothers (email: dbrothers@usgs.gov; @DBrothersSC), Pacific Coastal and Marine Science Center, U.S. Geological Survey (USGS), Santa Cruz, Calif.; Peter Haeussler, Alaska Science Center, USGS, Anchorage; Amy East, Pacific Coastal and Marine Science Center, USGS, Santa Cruz, Calif.; Uri ten Brink and Brian Andrews, Woods Hole Science Center, USGS, Mass.; Peter Dartnell, Pacific Coastal and Marine Science Center, USGS, Santa Cruz, Calif.; Nathan Miller, Woods Hole Science Center, USGS, Mass.; and Jared Kluesner, Pacific Coastal and Marine Science Center, USGS, Santa Cruz, Calif.
Citation: Brothers, D. S., P. Haeussler, A. East, U. ten Brink, B. Andrews, P. Dartnell, N. Miller, and J. Kluesner (2017), A closer look at an undersea source of Alaskan earthquakes, Eos, 98, https://doi.org/10.1029/2017EO079019. Published on 15 August 2017.

© 2017. The authors. CC BY-NC-ND 3.0

See the full article here .

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.

From Stanford: “Stanford researchers find similar characteristics in human-induced and natural earthquakes”

Stanford University

August 2, 2017
Danielle Torrent Tucker

A magnitude 5.6 earthquake likely induced by injection into deep disposal wells in the Wilzetta North field caused house damage in central Oklahoma on Nov. 6, 2011. Research conducted by Stanford scientists shows human-induced and naturally occurring earthquakes in the central U.S. share the same shaking potential and can thus cause similar damage. (Image credit: Brian Sherrod, USGS)

Whether an earthquake occurs naturally or as a result of unconventional oil and gas recovery, the destructive power is the same, according to a new study appearing in Science Advances Aug. 2. The research concludes that human-induced and naturally occurring earthquakes in the central U.S. share the same shaking potential and can thus cause similar damage.

The finding contradicts previous observations suggesting that induced earthquakes exhibit weaker shaking than natural ones. The work could help scientists make predictions about future earthquakes and mitigate their potential damage.

“People have been debating the strength of induced earthquakes for decades – our study resolves this question,” said co-author William Ellsworth, a professor in the Geophysics Department at Stanford’s School of Earth, Energy & Environmental Sciences and co-director of the Stanford Center for Induced and Triggered Seismicity (SCITS). “Now we can begin to reduce our uncertainty about how hard induced earthquakes shake the ground, and that should lead to more accurate estimates of the risks these earthquakes pose to society going forward.”

Induced quakes

Earthquakes in the central U.S. have increased over the past 10 years due to the expansion of unconventional oil and gas operations that discard wastewater by injecting it into the ground. About 3 million people in Oklahoma and southern Kansas live with an increased risk of experiencing induced earthquakes.

“The stress that is released by the earthquakes is there already – by injecting water, you’re just speeding up the process,” said co-author Gregory Beroza, the Wayne Loel Professor in geophysics at Stanford Earth and co-director of SCITS. “This research sort of simplifies things, and shows that we can use our understanding of all earthquakes for more effective mitigation.”

Oklahoma experienced its largest seismic event in 2016 when three large earthquakes measuring greater than magnitude 5.0 caused significant damage to the area. Since the beginning of 2017, the number of earthquakes magnitude 3.0 and greater has fallen, according to the Oklahoma Geological Survey. That drop is partly due to new regulations to limit wastewater injection that came out of research into induced earthquakes.

Stress drop

To test the destructive power of an earthquake, researchers measured the force driving tectonic plates to slip, known as stress drop – measured by the difference between a fault’s stress before and after an earthquake. The team analyzed seismic data from 39 manmade and natural earthquakes ranging from magnitude 3.3 to 5.8 in the central U.S. and eastern North America. After accounting for factors such as the type of fault slip and earthquake depth, results show the stress drops of induced and natural earthquakes in the central U.S. share the same characteristics.

A second finding of the research shows that most earthquakes in the eastern U.S. and Canada exhibit stronger shaking potential because they occur on what’s known as reverse faults. These types of earthquakes are typically associated with mountain building and tend to exhibit more shaking than those that occur in the central U.S. and California. Although the risk for naturally occurring earthquakes is low, the large populations and fragile infrastructure in this region make it vulnerable when earthquakes do occur.

The team also analyzed how deep the earthquakes occur underground and concluded that as quakes occur deeper, the rocks become stronger and the stress drop, or force behind the earthquakes, becomes more powerful.

“Both of these conclusions give us new predictive tools to be able to forecast what the ground motions might be in future earthquakes,” Ellsworth said. “The depth of the quake is also going to be important, and that needs to be considered as people begin to revise these ground-motion models that describe how strong the shaking will be.”

The scientists said that the types of rocks being exploited by unconventional oil and gas recovery in the U.S. and Canada can be found all over the world, making the results of this study widely applicable.

“As we can learn better practices, we can help ensure that the hazards induced earthquakes pose can be reduced in other parts of the world as well,” Ellsworth said.

Additional authors include lead author Yihe Huang, a former postdoctoral researcher at Stanford and now an assistant professor at the University of Michigan. The study was supported by the Stanford Center for Induced and Triggered Seismicity.

Media Contacts

Gregory Beroza
School of Earth, Energy & Environmental Sciences:
(650) 723-4958 (office)
(650) 319-5636 (cell)
beroza@stanford.edu

Danielle T. Tucker,
School of Earth, Energy & Environmental Sciences:
(650) 497-9541,
dttucker@stanford.edu

See the full article here .

You can help many citizen scientists in detecting earthquakes and getting the data to emergency services people in affected area.

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

Please help promote STEM in your local schools.

Stem Education Coalition

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

From temblor: “Earthquake offshore of Japan shakes crippled Fukushima Nuclear Power Plant”

temblor

July 20, 2017
David Jacobson

At 9:11 a.m. local time today, a M=5.8 earthquake struck offshore of Japan, near the Fukushima Nuclear Reactor, which was crippled in the M=9 Tohoku earthquake in 2011. Fortunately this quake was not large enough to cause any new damage to the reactor, which is expected to take at least four decades to dismantle. Two of the reasons why no damage occurred is because the quake was offshore and at a depth of 35 km, meaning only light shaking was felt in populated centers of Iwaki (Pop: 357,000) and Fukushima (Pop: 294,000). The USGS PAGER system estimates that should there be any economic losses, they will remain extremely minimal.

This Temblor map shows the location of today’s M=5.8 earthquake offshore of Japan. Also labeled is the location of the Fukushima Nuclear Power Plant, which was crippled in the 2011 M=9.0 Tohoku earthquake. Today’s earthquake was not large enough to cause additional damage to the plant, which will take at least four decades to dismantle.

Japan is one of the most seismically active countries on earth. Just off the eastern coast of the country are two subduction zones. In the southern part of the country is the Nansei-Shoto (Ryukyu) Trench, where there Philippine Sea plate subducts beneath the Eurasian Plate at rates varying from 47-61 mm/yr. To the north, is the Japan Trench, where the Pacific Plate subducts beneath the North American Plate at rates as high as 90 mm/yr (See USGS map below). What is also evident in this map is that northern Japan is much more seismically active than the southern portion of the country. While much of this can be attributed to aftershocks from the M=9.0 Tohoku earthquake there is still a greater rate of seismicity in the north. Based on the location of today’s M=5.8 earthquake, and its shallowly-dipping thrust focal mechanism, it likely occurred on the subducting slab, making this a late aftershock of the 2011 Tohoku quake.

This map from the USGS shows the tectonic regime around Japan. Included in this maps are M=6.0+ earthquakes since 1900, relative plate motion vectors, the subducting slabs (red, yellow, and blue lines), rupture zones (green polygons), and aftershock zones (pink polygons) from large earthquakes. The location of today’s M=5.8 earthquake has been added to this map to illustrate that it is likely a late aftershock from the 2001 M=9.0 Tohoku earthquake. (Map from USGS)

In terms of the seismic hazard of Japan, there are two schools of thought, which are heavily related to the recent seismicity and convergence rates. Below is a comparison of the Global Earthquake Activity Rate (GEAR) model, which is available in Temblor, and the Japan National Hazard Model. The GEAR model uses seismicity from the last 40 years and global strain rates to forecast the likely earthquake magnitude in your lifetime anywhere on earth, while the Japanese model estimates the likelihood of strong ground shaking. What is immediately evident is that the models are almost opposite one another. The GEAR model sees the lack of earthquakes and slower convergence rates near the Nankai Trough as an indication of lower seismic potential, whereas the Japanese model interprets it as an increased likelihood of a large magnitude earthquake. While it is entirely possible that a large quake could strike along the Nankai Trough, it should be pointed out that the Japanese model misses the hazard near the M=9.0 Tohoku earthquake, while the GEAR model shows an extremely high hazard.

This figure shows the Global Earthquake Activity Rate (GEAR) model, and the Japan National Seismic Hazard Model (J-SHIS). What is evident from these two models is that they are almost opposite one another.

Regardless of which model better depicts the seismic hazard of Japan, what is clear is that nearly the entire eastern seaboard is susceptible to seeing M=6.75 earthquakes. This translates into an extremely high awareness among residents. It is because of this that Japan is at the forefront of seismic safety, and often considered the country after which other countries should model their earthquake preparedness.

References [No links provided.]
USGS
Japan Seismic Hazard Information Station (J-SHIS)
9News

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

You can help many citizen scientists in detecting earthquakes and getting the data to emergency services people in affected area.

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

Earthquake country is beautiful and enticing

Almost everything we love about areas like the San Francisco bay area, the California Southland, Salt Lake City against the Wasatch range, Seattle on Puget Sound, and Portland, is brought to us by the faults. The faults have sculpted the ridges and valleys, and down-dropped the bays, and lifted the mountains which draw us to these western U.S. cities. So, we enjoy the fruits of the faults every day. That means we must learn to live with their occasional spoils: large but infrequent earthquakes. Becoming quake resilient is a small price to pay for living in such a great part of the world, and it is achievable at modest cost.

A personal solution to a global problem

Half of the world’s population lives near active faults, but most of us are unaware of this. You can learn if you are at risk and protect your home, land, and family.

Temblor enables everyone in the continental United States, and many parts of the world, to learn their seismic, landslide, tsunami, and flood hazard. We help you determine the best way to reduce the risk to your home with proactive solutions.

Earthquake maps, soil liquefaction, landslide zones, cost of earthquake damage

In our iPhone and Android and web app, Temblor estimates the likelihood of seismic shaking and home damage. We show how the damage and its costs can be decreased by buying or renting a seismically safe home or retrofitting an older home.

Please share Temblor with your friends and family to help them, and everyone, live well in earthquake country.

Temblor is free and ad-free, and is a 2017 recipient of a highly competitive Small Business Innovation Research (‘SBIR’) grant from the U.S. National Science Foundation.

ShakeAlert: Earthquake Early Warning

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 by 2018.

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, depending on the distance to the epicenter of the earthquake. For very large events like those expected on the San Andreas fault zone or the Cascadia subduction zone the warning time could be much longer because the affected area is much larger. ShakeAlert can give enough time to slow and stop 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 by 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” test 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. This “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

From temblor: “M=6.7 earthquake near Greek and Turkish tourist hotspots likely ruptured the Gökova Fault”

temblor

July 20, 2017
Volkan Sevilgen
Ross S. Stein
David Jacobson

The Greek island of Kos sustained heavy damage in the 21 July M=6.7 earthquake. Both of the known fatalities in the earthquake occurred on the island. (Photo from: http://www.holidaypirates.com)

The large earthquake struck at 1:40 am local time near the tourist meccas of Kos, Greece, and Bodrum, Turkey. It was preceded by a M=2.5 shock approximately 20 minutes before the mainshock. The earthquake occurred at a relatively shallow depth of 10 km, and strong shaking lasted for about 20 seconds. Despite this, there are only two confirmed fatalities, both of which were tourists. Based on reports, and pictures coming in from Greece and Turkey, the majority of damage appears to have occurred on Kos (see below), where there are currently over 200,000 holidaymakers, according to officials on the island. In addition to the two deaths, hundreds of people have been injured in both Greece and Turkey, with most of these due to falling debris and collapsing structures. Following the mainshock, there was also a small tsunami recorded by tide gages, with the sea dropping by up to 25 cm (1 ft) before cresting at about 5-10 cm (2-5 inches) above normal. While the USGS and European-Mediterranean Seismological Centre report the earthquake’s magnitude as 6.7, the Kandilli Observatory in Turkey assigns it a magnitude of 6.5.

Earthquakes are from the European Mediterranean Seismic Centre (EMSC), and the faults are from the Turkish Mineral Research and Exploration Institute (MTA). We have dotted in the likely westward extension of the Gökova Fault. However, Kurt et al (1999) propose a set of smaller faults offshore, which could have instead been activated in this event.

The Cactus Bar on the Greek island of Kos sustained heavy damage in the 21 July M=6.7 earthquake. (Photo from: http://www.thesun.co.uk)

At least six centuries of quiet

No large historical shock is known along this fault (based on the GEM Historical Earthquake Catalog), although in 1863, a M~7.5 earthquake occurred about 75 km (40 mi) to the south. The Bodrum Castle was built in 1402 by the Knights of St. John, and so over 600 years had elapsed without a large event.

Bodrum (source: http://bareboatsailingholidays.com/destinations/turkey/the-carian-coast/bodrum/)

The earthquake focal mechanism released by the USGS is consistent with extension along a WNW-striking fault inclined about 56° to the Earth’s surface. This looks to us most consistent with the quake rupturing a western extension of the mapped Gökova Fault. If so, there remains a roughly 100-km-long (60 mi) unruptured section of the fault, with the potential to produce a M~7.3 shock. This entire area is currently filled with summer tourists enjoying the beaches and antiquities of this region, and so people should take precautions and remain outside of ancient stone buildings.

The occurrence of large, damaging shock after a long hiatus is a reminder that active faults should be respected as sentinels of seismic risk, and we should build and prepare accordingly.

References [Sorry, no links provided.]

European Mediterranean Seismic Centre (EMSC)
Turkish Mineral Research and Exploration Institute (MTA)
Global Earthquake Model Foundation’s Historical Earthquake Catalog (GEM)
U.S. Geological Survey (USGS)
Hulya Kurt, Emin Demirbag, Ismail Kuscu (1999), Investigation of the submarine active tectonism in the Gulf of Go ̈kova, southwest Anatolia–southeast Aegean Sea, by multi-channel seismic reflection data, Tectonophysics 305, 477–496 http://web.itu.edu.tr/kurt/publication_pdfs/A01-tectono99-gokova.pdf

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

You can help many citizen scientists in detecting earthquakes and getting the data to emergency services people in affected area.

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

Earthquake country is beautiful and enticing

Almost everything we love about areas like the San Francisco bay area, the California Southland, Salt Lake City against the Wasatch range, Seattle on Puget Sound, and Portland, is brought to us by the faults. The faults have sculpted the ridges and valleys, and down-dropped the bays, and lifted the mountains which draw us to these western U.S. cities. So, we enjoy the fruits of the faults every day. That means we must learn to live with their occasional spoils: large but infrequent earthquakes. Becoming quake resilient is a small price to pay for living in such a great part of the world, and it is achievable at modest cost.

A personal solution to a global problem

Half of the world’s population lives near active faults, but most of us are unaware of this. You can learn if you are at risk and protect your home, land, and family.

Temblor enables everyone in the continental United States, and many parts of the world, to learn their seismic, landslide, tsunami, and flood hazard. We help you determine the best way to reduce the risk to your home with proactive solutions.

Earthquake maps, soil liquefaction, landslide zones, cost of earthquake damage

In our iPhone and Android and web app, Temblor estimates the likelihood of seismic shaking and home damage. We show how the damage and its costs can be decreased by buying or renting a seismically safe home or retrofitting an older home.

Please share Temblor with your friends and family to help them, and everyone, live well in earthquake country.

Temblor is free and ad-free, and is a 2017 recipient of a highly competitive Small Business Innovation Research (‘SBIR’) grant from the U.S. National Science Foundation.

ShakeAlert: Earthquake Early Warning

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 by 2018.

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, depending on the distance to the epicenter of the earthquake. For very large events like those expected on the San Andreas fault zone or the Cascadia subduction zone the warning time could be much longer because the affected area is much larger. ShakeAlert can give enough time to slow and stop 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 by 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” test 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. This “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

From temblor: “State finds new active fault strands in Santa Monica, Beverly Hills, and Hollywood”

temblor

July 18, 2017
David Jacobson
Ross Stein

On 13 July, the California Geological Survey released four preliminary Earthquake Fault Zone maps for parts of Los Angeles and Napa counties. The West Los Angeles coverage provides new active fault ‘traces’ (where a fault intersects the Earth’s surface) and ‘zones’ (the areas in which some faulting could occur in an earthquake) for the Santa Monica Fault, the Hollywood Fault, and the Newport-Inglewood Fault. And, yes, the Hollywood Fault is responsible for lifting up one of L.A.’s most sacred landmarks, the “Hollywood” sign atop the Santa Monica Mountain range.

New Fault Zone Mapping

Because fault sections were added, revised, and removed, trillions of dollars of real estate is impacted by these new boundaries. This work is carried out under California law; if property lies within the Alquist-Priolo Earthquake Fault Zones that generally extend 150 meters to each side of a fault, special investigation is required prior to construction. These are preliminary review maps, which will not become official until at least January 11, 2018, but provide a chance to see what new fault research has revealed about the Hollywood, Santa Monica, and Newport-Inglewood Faults, which traverse a wealthy, densely-populated urban corridor.

This map shows the old (current) and new (proposed) faults and ‘Alquist-Priolo’ Fault Zones for west Los Angeles. The preliminary “review maps” released by the California Geological Survey last week reveal a greater area at risk of experiencing earthquake slip. The new, higher resolution fault mapping in red can be compared to the cruder older mapping in blue. The revised Santa Monica Fault would be capable of M=6.7 earthquake. (Data from: California Geological Survey)

The Fault Zones limit residential and commercial development

Alquist-Priolo Zones are defined as regulatory perimeters around active faults. According to Tim Dawson, a senior engineering geologist for the California Geological Survey, these zones are “intended to capture the most hazardous faults that could produce surface displacements of concern to a building.” While a fault rupture can be confined to zones just a few meters (10 ft), because of the uncertainty of the fault location and the possibility of slip on a distributed band of faults, the state makes the zones ~150 meters (500 ft) on either side of the mapped trace of a fault.

If a property is within a Fault Zone, strict guidelines must be followed if new construction or major renovations are planned. Further, development is prohibited directly on active faults found within these zones . All of this is done to ensure public safety. Therefore, new maps like the ones released last week will have significant impacts.

High resolution fault mapping is extremely difficult in densely populated and heavily landscaped areas. Brian Olson, a California Geological Survey engineering geologist used existing maps, radar topographic imagery (LIDAR), old aerial photos, and field observations.

Dr. Rufus Catchings of the U.S. Geological Survey performed a shallow geophysical survey that determined the subsurface geometry of the Santa Monica Fault in the vicinity of the Veterans Administration Hospital (Catchings et al., 2008).

Additionally, Tim Dawson said that, “Professor James Dolan at USC conducted a paleoseismic investigation at the Veterans Administration Hospital on the Santa Monica fault. Other faults studies have been conducted by consultants at schools in the area, as well as other studies done for the proposed LA Metro Purple Line Subway Extension.” In the map above, the old and new fault traces and Alquist-Priolo (A-P) Zones are shown to illustrate the changes. One of these changes is the addition of a 6.3 km2 zone cutting through Beverly Hills, Westwood and Santa Monica.

Which fault sections disappeared, and which were added?

The southernmost 5 km (3 mi) section of the Santa Monica Fault, which formerly sliced through a coveted beach community, has been removed. The fault should have been visible in the Santa Monica bluff face, and probably was not found. This trace also was not expressed in the topography, another clue that it had been mislocated. The central two sections remained, and a new one was added to the north. So, in effect, the fault has migrated closer to the range front of the Santa Monica Mountains.

Prior to the new mapping, there were four discontinuous faults running through Santa Monica. Now, the 5-km-long (3 mi) northern-most section of the Newport-Inglewood Fault, which ruptured in the 1933 M=6.4 Long Beach earthquake, has been removed entirely, and so the Newport-Inglewood and Santa Monica Faults are no longer connected.

What does this mean for earthquake rupture?

But there is now more connectivity and continuity between the Hollywood and Santa Monica Faults, making a through-going rupture more likely, which, if it encompassed the adjacent Raymond Fault could reach Magnitude~7. On the other hand, the possibility of a joint rupture of the northern Newport-Inglewood and Santa Monica Faults is now diminished. The revised 12 km-long fault section of the Santa Monica fault has a high degree of continuity, permitting a M≤6.7 rupture, similar to the 1971 San Fernando or 1994 Northridge earthquake.

Fault traces to green belts

Wouldn’t it be ideal if all these fault traces were turned into green belts? This would be the most appropriate and most valuable use of this land.

Just imagine if all fault traces running through urban areas were turned into green belts like this. (Photo from: Pinterest)

The Right Stuff

These changes in fault traces highlight the importance of continually researching and remapping urban faults, as only with better knowledge can we prepare for the earthquakes which will inevitably happen. Nowhere is this more difficult—or more important—than in dense urban areas like this one.

References
California Geological Survey Press Release dated July 13, 2017: Link

California Geological Survey PDF Map for Preliminary Review: Link

Webpage for the Alquist-Priolo Earthquake Fault Zoning Act: Link

Rong-Gong Lin II and Raoul Rañoa, ‘Earthquake fault maps for Beverly Hills, Santa Monica and other Westside areas could bring development restrictions’ (Los Angeles Times, 13 July 2017): Link

R. D. Catchings, G. Gandhok, M. R. Goldman, D. Okaya, M. J. Rymer, and G. W. Bawden, Near-Surface Location, Geometry, and Velocities of the Santa Monica Fault Zone, Los Angeles, California, Bulletin of the Seismological Society of America, Vol. 98, No. 1, pp. 124–138, February 2008, doi: 10.1785/0120020231.

Olson, Brian, 2017, The Hollywood, Santa Monica, and Newport-Inglewood Faults in the Beverly Hills and Topanga 7½-minute Quadrangles, Los Angeles County, California: California Geological Survey, Fault Evaluation Report #259, 72 pages of text and figures; Plate 1, Compilation of Historical Fault Mapping; Plate 2, Geomorphology of Beverly Hills and Topanga Quadrangles; Plate 3, Recommended Fault Zones for Hollywood Fault, Newport-Inglewood Fault, and Santa Monica Fault.

Acknowledgements
We would like to thank Tim Dawson (California Geological Survey) and Robert H. Sydnor for reviewing this post and for providing valuable insight.

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

You can help many citizen scientists in detecting earthquakes and getting the data to emergency services people in affected area.

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

Earthquake country is beautiful and enticing

Almost everything we love about areas like the San Francisco bay area, the California Southland, Salt Lake City against the Wasatch range, Seattle on Puget Sound, and Portland, is brought to us by the faults. The faults have sculpted the ridges and valleys, and down-dropped the bays, and lifted the mountains which draw us to these western U.S. cities. So, we enjoy the fruits of the faults every day. That means we must learn to live with their occasional spoils: large but infrequent earthquakes. Becoming quake resilient is a small price to pay for living in such a great part of the world, and it is achievable at modest cost.

A personal solution to a global problem

Half of the world’s population lives near active faults, but most of us are unaware of this. You can learn if you are at risk and protect your home, land, and family.

Temblor enables everyone in the continental United States, and many parts of the world, to learn their seismic, landslide, tsunami, and flood hazard. We help you determine the best way to reduce the risk to your home with proactive solutions.

Earthquake maps, soil liquefaction, landslide zones, cost of earthquake damage

In our iPhone and Android and web app, Temblor estimates the likelihood of seismic shaking and home damage. We show how the damage and its costs can be decreased by buying or renting a seismically safe home or retrofitting an older home.

Please share Temblor with your friends and family to help them, and everyone, live well in earthquake country.

Temblor is free and ad-free, and is a 2017 recipient of a highly competitive Small Business Innovation Research (‘SBIR’) grant from the U.S. National Science Foundation.

ShakeAlert: Earthquake Early Warning

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 by 2018.

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, depending on the distance to the epicenter of the earthquake. For very large events like those expected on the San Andreas fault zone or the Cascadia subduction zone the warning time could be much longer because the affected area is much larger. ShakeAlert can give enough time to slow and stop 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 by 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” test 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. This “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