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

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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

From temblor: “M=4.2 earthquake in Oklahoma widely felt throughout Midwest”

temblor

July 14, 2017
David Jacobson

Shaking from today’s M=4.2 earthquake was widely felt in Oklahoma’s capital of Oklahoma City.

At 8:47 a.m. local time this morning, a M=4.2 earthquake struck central Oklahoma in between the cities of Oklahoma City, Tulsa, and Stillwater. This was followed by five aftershocks, the largest of which was a M=3.8. At 10 a.m. local time, there have been over 1,500 felt reports from the mainshock on the USGS website, from all over the state of Oklahoma, and even in Wichita, Kansas, over 200 km away. So far, there are no reports of damage, which is unlikely given this quake’s moderate magnitude. Additionally, the USGS PAGER system estimates that economic losses should remain extremely minimal, and any fatalities are very unlikely.

This Temblor map shows the location of today’s M=4.2 earthquake in Oklahoma. This quake was widely felt throughout the state, and was also felt in 4 other surrounding states based on USGS felt reports.

According to the USGS, today’s earthquake occurred at a depth of 9.3 km, and was right-lateral strike-slip in nature. This depth is relatively deep for Oklahoma, but still within the range frequently seen. Based on the fault map shown in the Temblor map above, and the strike-slip component of today’s earthquake, it occurred on an unmapped fault in the region. However, the orientation of the structure on which the quake struck is consistent with the regional compression direction outlined in Walsh and Zoback, 2016. Also labeled in the Temblor map is the large northeast-southwest-trending Wilzetta Fault. Based on this fault’s strike (northeast-southwest) and the regional compression, it is not at the preferred orientation to undergo a large rupture. This is good as given its length, it is capable of producing a large magnitude earthquake. Instead, faults with orientations similar to the fault on which today’s quake occurred have a higher likelihood of rupturing.

While when most people think of earthquakes in Oklahoma, they think of induced quakes, based on Walsh and Zoback, 2016, there are no high output disposal wells in the area around today’s earthquake. While it is possible that in the last two years more wells have been put in, this is unlikely since following the 2016 M=5.8 Pawnee earthquake, disposal has been limited around the state. Therefore, today’s quake may have been more natural than many that occur in the state.

Because Temblor does not factor in induced seismicity into the Hazard Rank, we must examine a Petersen et al., 2017 study in which both natural and induced seismicity is factored into the likelihood of damage. The map below shows the chance of damage from an earthquake in 2017 for the entire country. What may be eye-opening is that Oklahoma City has a higher likelihood of experiencing earthquake damage this year than both San Francisco and Los Angeles.

The 2017 seismic hazard forecast map reveals that Oklahoma City actually has a higher threat of experiencing a damaging earthquake than San Francisco and Los Angeles. (Figure from Petersen et. al., 2017)

References
USGS

F. Rall Walsh, III, and Mark D. Zoback, Probabilistic assessment of potential fault slip related to injection-induced earthquakes: Application to north-central Oklahoma, USA, 2016, Geology, doi:10.1130/G38275.1

Mark D. Petersen, Charles S. Mueller, Morgan P. Moschetti, Susan M. Hoover, Allison M. Shumway, Daniel E. McNamara, Robert A. Williams, Andrea L. Llenos, William L. Ellsworth, Andrew J. Michael, Justin L. Rubinstein, Arthur F. McGarr, and Kenneth S. Rukstales, 2017 One-Year Seismic-Hazard Forecast for the Central and Eastern United States from Induced and Natural Earthquakes, Seismological Research Letters, March 2017; 88 (2A), DOI: 10.1785/0220170005

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=6.4 earthquake strikes off the coast of Papua New Guinea”

temblor

July 13, 2017
David Jacobson

Today’s M=6.4 earthquake in Papua New Guinea struck near the island of New Ireland, in the eastern part of the country. (Photo from: Simon’s Jam Jar)

At 3:36 a.m. local time, a M=6.4 earthquake struck Papua New Guinea just off the island of New Ireland. The eastern part of the country is sparsely populated meaning people were only exposed to light and lesser degrees of shaking. Because of this damage and fatalities are unlikely, and so far no reports of them have come in. Another reason why strong shaking was not felt is because the earthquake occurred offshore and at a depth of 47 km, according to the USGS (The European-Mediterranean Seismological Centre assigned it a depth of 40 km). Based on the USGS focal mechanism, this earthquake was thrust in nature. While compressional earthquakes are common in this region, given the proximity to the New Britain Trench, the strike of today’s earthquake makes it hard to reconcile.

This Temblor map shows the location of today’s earthquake in Papua New Guinea. While this earthquake was compressional in nature, based on the quake’s strike, it was likely not associated with subduction at the New Britain Trench.

In the region around today’s earthquake, much of the seismicity is dominated by the subduction of the Australian Plate. North of the New Britain Trench, the Pacific Plate has been broken up into numerous microplates, all of which are being pushed in various directions. In the USGS map below, relative plate motions are shown, illustrating the complex dynamics of the region. Because of these plate motions, strike-slip and extensional earthquakes are also common. Nonetheless, large subduction zone earthquakes, including a M=7.9 in December 2016 are the events which cause the most damage and fatalities.

This map from the USGS shows historical seismicity and relative plate motions in the region around today’s M=6.4 earthquake (yellow star). What this map illustrates is that rapid deformation and high rates of seismicity is due to relative motion exceeding 100 mm/yr. In this map, one can see that the majority of quakes are associated with subduction at the New Britain Trench. (Map from USGS)

Based on the Global Earthquake Activity Rate (GEAR) model, which is available in Temblor, today’s earthquake should not be considered surprising. This model uses global strain rates and seismicity since 1977 to forecast the likely earthquake magnitude in your lifetime anywhere on earth. From this model, which is in the figure below, one can see that a M=7.75+ earthquake is likely in your lifetime in this area. Such a large magnitude is likely because the area is undergoing rapid deformation due to plate motions of upwards of 100 mm/yr. Should there be any large aftershocks (so far there is only one M=4.8 in our catalog) we will update this post.

This Temblor map shows the Global Earthquake Activity Rate (GEAR) model for the region around Papua New Guinea. This model uses global strain rates and seismicity since 1977 to forecast the likely earthquake magnitude in your lifetime anywhere on earth. From this model, one can see that today’s M=6.4 earthquake should not be considered surprising as a M=7.75+ quake is possible.

References [No links provided.]
USGS
European-Mediterranean Seismological Centre

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: “A M=7 aftershock is 300 times more likely in the week after a M=7 mainshock in new study”

temblor

July 11, 2017
David Jacobson
Ross Stein

In a new study which will be published tomorrow, the effects of aftershocks in the week following a M=7.0 earthquake are shown to elevate the potential for a second M=7.0 by up to 300 times. This photo shows the San Andreas Fault, which takes center stage in this expansion on the already existing California earthquake hazard model.

Tomorrow, a new study on the California earthquake hazard model will be published, which shows, through computer simulations, that in the week following a M=7.0 earthquake, the likelihood of another M=7.0 quake is up to 300 times greater than the week beforehand. This dramatic jump in likelihood is due to the inclusion of the short-term probabilities associated with aftershock sequences, a factor never before used in statewide comprehensive model like this one.

The California earthquake hazard model, the Uniform California Earthquake Rupture Forecast Version 3 (UCERF3), was first published in 2015, and quantifies the hazard posed by tectonic forces unleashed on faults. The 2015 model was the first to include the possibility that an earthquake on one fault could jump to another fault in a matter of seconds, thereby creating multi-fault ruptures. In doing so, over 250,000 rupture scenarios were created for the state of California, vastly more than in the previous model. The reality of such falling-domino or ‘cascading’ ruptures was demonstrated spectacularly in the 2002 M=7.9 Denali, Alaska, and the 2016 M=7.8 Kaikoura, New Zealand earthquakes.

It the study released tomorrow, dubiously dubbed UCERF3-ETAS (ETAS refers to ‘epidemic-type aftershock sequence’ a concept borrowed from medical research and successfully applied to earthquakes by Yoshihito Ogata of Japan) takes it a step further by attempting to capture the role of aftershocks of all sizes following a mainshock. In a nutshell, for short times after a mainshocks, aftershocks matter.

These figures shows the simulated potential M=2.5+ aftershocks in the week after both a M=7.0 Southern San Andreas earthquake, and a M=7.1 quake on the Hayward Fault running through the East Bay. This figure highlights the potential domino-effect seen by a large earthquake. (Figure from: Field et al., 2017)

Mainshocks, by changing the stress on surrounding faults, trigger aftershocks; if you like, the mainshocks are the ‘parents.’ But these aftershock ‘daughters’ can in turn trigger ‘grand-daughters’ aftershocks of their own, ad infinitum. While most aftershocks of any generation will be smaller than their mainshock, occasionally they will be the same size as their mainshock, and rarely they will be larger. This is contrary to the popular belief that for a M=7 quake, the largest aftershock will be less than M=6. By including this triggering potential and running hundreds of thousands of simulations, what you see as Dr. Field described it, are faults as “conduits of hazard” which appear like blood pumping through veins. It is important to point out that what we are seeing in these figures are not dynamically-triggered remote earthquakes, but rather the potential for one large earthquake to trigger another, and then perhaps another.

The study’s team had to choose an arbitrary time period for consideration. Because aftershocks rapidly decay in time, shorter the period, the greater the gain in triggering likelihood. They chose a week as being societally relevant. Nonetheless, the effects are also given for longer time periods such as a month and a year following a mainshock to illustrate the decayed effects over time. The figure above shows the simulated potential M=2.5+ aftershocks in the week after both a M=7.0 earthquake on the southern San Andreas, and a M=7.1 quake on the Hayward Fault running through the East Bay.

We consider their result an important advance, but there is still room for improvement. The figure below shows the simulated potential M=2.5+ aftershocks in the week after a M=6.1 earthquake along the Parkfield section of the San Andreas, shown in two ways. Such M~6.1 earthquakes have struck this portion of the San Andreas every 20-40 years, the most recent in 2004. The image on the right does not take faults into account, resulting in an idealized halo of simulated aftershocks. But it looks nothing like the actual Parkfield aftershock zones, or any other, which are never halos and often illuminate triggering lobes. Coulomb stress transfer gives this spatial pattern, and and so controls which faults are more likely, and which are less likely, to rupture next. That, in our judgement, is what is missing from this approach. While Dr. Field said in an interview that fault characteristics, such as magnitude-frequency distributions, are incorporated, it is still largely lacks Coulomb stress transfer, and that could come next.

This figure shows how by incorporating the effect an earthquake has on nearby faults, you go from the idealized halo not representative of aftershock sequences (left), to a model which has the appearance of blood being pumped through veins. While this model is a step in the right direction, it still does not incorporate which faults are brought closer to failure, which is required for fault rupture. (Figure from: Field et al., 2017)

The Field et al. study takes a great step forward in quantifying the short-term consequences of a large earthquake. In the week following a large magnitude earthquake the potential for a second large quake can increase 300 times; in the year after the mainshock, the gains are typically a factor of 10 according to Dr. Field.

The message is this: Unfortunately, after a large quake, it may not be over. Instead, there is a chance that the sequence has just begun, and could spawn daughters greater than their parents—as all children aim to be.

References [Sorry, no links provided]

Edward H. Field, Thomas H. Jordan, Morgan T. Page, Kevin R. Milner, Bruce E. Shaw, Timothy E. Dawson, Glenn P. Biasi, Tom Parsons, Jeanne L. Hardebeck, Andrew J. Michael, Ray J. Weldon II, Peter M. Powers, Kaj M. Johnson, Yuehua Zeng, Karen R. Felzer, Nicholas van der Elst, Christopher Madden, Ramon Arrowsmith, Maximilian J. Werner, and Wayne R. Thatcher, A Synoptic View of the Third Uniform California Earthquake Rupture Forecast (UCERF3), Seismological Research Letters Volume 88, Number 5, doi: 10.1785/0220170045

Field, E. H., K. R. Milner, J. L. Hardebeck, M. T. Page, N. van der Elst, T. H. Jordan, A. J. Michael, B. E. Shaw, and M. J. Werner (2017). A spatiotemporal clustering model for the Third Uniform California Earthquake Rupture Forecast (UCERF3-ETAS): Toward an operational earthquake forecast, Bull. Seismol. Soc. Am. 107, doi: 10.1785/0120160173.

Personal correspondence with Dr. Edward (Ned) Field (USGS – Golden, Colorado)

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

From temblor: “Deep M=6.9 earthquake in Guatemala possibly preceded by foreshock sequence”

temblor

June 14, 2017
David Jacobson

Guatemala City, approximately 160 km from the epicenter of today’s M=6.9 earthquake experienced moderate shaking. While there are only reports of moderate damage throughout the country, it was very widely felt. (Picture from: imgix.net)

At 1:29 a.m. local time, a M=6.9 earthquake struck western Guatemala near the border with Mexico. Despite the quake’s deep depth (94 km according to the USGS) it was widely felt throughout Central America, including in Guatemala City 160 km away, which is home to 3.3 million people. According to officials in Guatemala, landslides were triggered, blocking highways, and houses were moderately damaged. Fortunately, the region around the epicenter, which, based on the USGS ShakeMap experienced strong shaking, is mountainous and sparsely populated and there is only one known injury. Across the border in Mexico, minor damage was also sustained.

This Temblor map shows the location of today’s M=6.9 earthquake in western Guatemala. Also included in this map is the location of the M=7.5 earthquake in 1976 that killed nearly 23,000 people. The thick red line around this epicenter is the fault rupture area.

This part of Central America is highly seismically active due to a combination of relative plate motions. Off the southern coast, the Cocos Plate is subducting beneath both the North American and Caribbean plates. Additionally, left-lateral strike slip motion is also present in much of eastern and central Guatemala due to the active plate boundary between the North American and Caribbean plates. This means that Guatemala sits on what is known as a triple junction, where three tectonic plates meet.

As a result, this region has experienced large, damaging earthquakes, including a M=7.5 earthquake in 1976 in eastern Guatemala that killed nearly 23,000 people and left more than 75,000 injured (Olcese et al., 1977). That devastating quake occurred at a depth of 5 km, and was on the Motagua Fault, which is a pure left-lateral strike-slip fault. In comparison, today’s quake was almost purely extensional and occurred at the much greater depth of 94 km (according to the USGS). While the location and depth of the earthquake suggests that the rupture occurred near the subducting slab, its extensional nature indicates that it may have been caused by localized steepening of the slab.

While today’s earthquake and the deadly one in 1976 were vastly different in their nature and impact on the region, they highlight an important earthquake characteristic: depth. Even had today’s earthquake been a M=7.5, like the one in 1976, it would not have caused as much damage, because it occurred at a depth 19 times greater. This is because significant energy is lost, resulting in less shaking at the surface. In the side-by-side figures below, USGS ShakeMaps are shown for today’s earthquake, and the one in 1976. From these, one can see that while violent shaking was felt in the 1976 quake, today’s shaking only reached strong levels.

These USGS ShakeMaps show shaking in today’s M=6.9 earthquake (left) and the M=7.5 earthquake in 1976 (right). What is clear in these figures is that shaking levels were significantly higher in the 1976 earthquake. This was due to the fact that the magnitude was greater, and because it occurred at a shallow depth.

Another aspect of this quake which deserves extra attention is that in the nine hours prior to the M=6.9 mainshock, there were five smaller magnitude earthquakes, ranging from M=4.4 to M=5.6, just offshore. Two of these occurred within an hour of the M=6.9, including one just 6 minutes prior. While not necessarily indicative of foreshock events, given they were over 100 km away, the rate at which they occurred is substantially higher than the normal background rate. Therefore, if they were foreshocks, they could indicate that a larger creep event took place at the Middle America Trench. While creep events do not necessarily precede large earthquakes, if this area along the subduction zone were to rupture, a M+7.5 earthquake could result. This would generate severe shaking along the Central American coastline, and could trigger a tsunami. Therefore, these smaller events that preceded the mainshock deserve attention.

Because of the complex tectonic environment on which Honduras, and the rest of Central America sits, large earthquakes should be expected. Using the Global Earthquake Activity Rate (GEAR) model, which is available in Temblor, we can see what the likely earthquake magnitude in your lifetime is anywhere on earth. While today’s quake is deeper than GEAR takes into account, we can still see in the map below that for much of central, western, and southern Guatemala, M=6.75+ earthquakes should be expected. Because of this, residents of the small country should be prepared for, and understand the regional earthquake hazards.

This Temblor map shows the Global Earthquake Activity Rate (GEAR) model for much of Central America. While today’s earthquake is deeper than is considered by GEAR, it does show that M=6.75+ earthquakes are likely to occur in your lifetime in much of central, western, and southern Guatemala. The GEAR model uses global strain rates and seismicity since 1977 to produce an earthquake forecast.

References
USGS
European-Mediterranean Seismological Centre
Associated Press
A. F. Espinosa, The Guatemalan earthquake of February 4, 1976, a preliminary report, Professional Paper 1002, 1976

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

From Temblor: “The San Andreas’ sister faults in Northern California”

temblor

May 23, 2017
David Jacobson

Check your hazard rank

The city of Ukiah, in Northern California sits right next to the Maacama Fault, which is capable of M=7.5 earthquakes and poses a significant threat to the region. (Photo from: Trulia)

In California, when most people think about faults, their thoughts are immediately drawn to the San Andreas, and to a lesser extent, the Hayward Fault. However, in Northern California, there is almost no seismicity on the San Andreas. Instead, the majority of the earthquakes occur on faults that are parallel to and east of the San Andreas. These faults are part of the greater San Andreas system, and are capable of generating large magnitude earthquakes. Today, we thought we’d take a look at two of them.

The Maacama and Bartlett Spring faults lie approximately 50 km and 80 km east of the San Andreas respectively. All of these faults are members of the greater transform boundary between the Pacific and North American plates, a margin primarily composed of nearly pure right-lateral strike-slip faults. Both the Maacama and Bartlett Springs faults are known to be active based on seismicity and creep. Creep implies there is very slow, relatively continuous motion on a fault due to tectonic deformation. While faults that creep tend to not rupture in large earthquakes, the Hayward Fault running through the San Francisco East Bay creeps and has ruptured in M=7+ quakes. So, it is not a black and white rule.

This Temblor map shows the major faults in Northern California. What is evident from this map is that the San Andreas shows almost no seismicity, which the Maacama and Bartlett Springs faults shows significant activity. It should be pointed out that the cluster of earthquakes south of Clear Lake are hydrothermally induced.

What is evident from the Temblor map above is that within the last month, there has been microseismicity along both the Maacama and Bartlett Springs faults. By examining the USGS database, it was determined that the seismicity in the last month is relatively consistent with previous months. While almost none of these quakes were felt, they highlight an obvious difference with the San Andreas. In the last month, there have been no M=1+ earthquakes on the northern San Andreas Fault. In fact, the portion of the San Andreas that ruptured in the 1906 earthquake (From San Juan Bautista to the Mendocino Triple Junction) shows almost no signs of seismic activity. What this shows that if we only used seismicity to identify faults, we would miss the greatest threat Northern California faces.

While the San Andreas may be capable of producing larger earthquakes than either the Maacama or Bartlett Spring faults, quakes on both of these could be very damaging. Based on their relative lengths, M=7.5 earthquakes are possible on either the Maacama or Bartlett Springs faults. Such quake could be devastating to the city of Ukiah, which sits right on the Maacama Fault. Based on the Global Earthquake Activity Rate model, which is available in Temblor, the likely earthquake in your lifetime for this part of California is M=6.25+. This model uses global strain rates and seismicity since 1977 to forecast future events. What this suggests is that a M=7.5 earthquake would be a unique event, but nonetheless possible.

This Temblor map shows the Global Earthquake Activity Rate (GEAR) model for Northern California. What this shows is that around the Maacama and Bartlett Springs faults, a M=6.25+ earthquake is likely in your lifetime.

The Maacama Fault also deserves a bit of extra attention because at its southernmost extent in Santa Rosa, there is a stepover with the Rodgers Creek Fault. Because of their close proximity, it is possible that an earthquake originating on the Rodgers Creek Fault, could rupture onto the Maacama Fault, or vice versa. This has serious implications for the city of Santa Rosa, which suffered heavy damage in the 1906 earthquake (see below). What all of this indicates is that while the San Andreas may get all the publicity, Northern California has many other large faults capable of generating large earthquakes.

This picture shows the city of Santa Rosa following the 1906 earthquake. The caption in this figure reads: “Dear Blossom, This is as we found it. Much love, Mother.”

References
USGS

Ohlin, H.N., McLaughlin, R.J., Moring, B.C., and Sawyer, T.L., 2010, Geologic map of the Bartlett Springs Fault Zone in the vicinity of Lake Pillsbury and adjacent areas of Mendocino, Lake, and Glenn Counties, California: U.S. Geological Survey Open-File Report 2010–1301, scale 1:30,000. (Available at https://pubs.usgs.gov/sim/3125/.)

Robert J. McLaughlin, Andrei M. Sarna-Wojcicki, David L. Wagner, Robert J. Fleck, V.E. Langenheim, Robert C. Jachens, Kevin Clahan, and James R. Allen, Evolution of the Rodgers Creek–Maacama right-lateral fault system and associated basins east of the northward-migrating Mendocino Triple Junction, northern California, 2012, Geosphere, Vol. 8, Issue 2, DOI:10.1130/GES00682.1

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