From temblor: “Albania earthquake strikes highest-hazard zone in the Balkans, devastating nearby towns”

From temblor

November 26, 2019
by Ross S. Stein, Ph.D., and Volkan Sevilgen, M.Sc., Temblor, Inc.

As of today, some 24 people are dead and 650 injured, and many more are unaccounted for in collapsed concrete buildings on the coastal plains surrounding the epicenter. The quake likely struck on a ‘blind thrust fault’ that does not reach the Earth’s surface but had nevertheless been previously identified by geologists.

It could have been worse

On 26 Jul 1963, some 165 km (100 mi) east of the 26 Nov 2019 Mag. 6.4 Albania shock, a Mag. 6.1 earthquake struck Skopje, capital of Northern Macedonia destroying 80% of the city, killing over 1,070 people, injuring 3,000-4,000, and leaving more than 200,000 people homeless.

It would appear that the 26 Nov 2019 quake, although 5 times larger than the Skopje event, did much less damage, perhaps because it struck more than 35 km from the 375,000 people living in the Albanian capital of Tirana.

Map showing Temblor’s globally consistent PUSH (Probabilistic Uniform Seismic Hazard) model, together with earthquakes principally from the EMSC catalog. The region is one in which residents should expect powerful shaking in their lifetimes. The aftershock distribution is roughly perpendicular to the presumed NW-SE oriented thrust fault.

Immediate foreshocks and remote aftershocks

The M 6.4 quake was preceded during the previous 6 hours by four M3 shocks in the epicentral region, the largest of which was Mag. 4.4, striking 1 hour before the mainshock. While uncommon, this kind of activity does not make earthquake prediction any easier, because the foreshocks do not show any features that would distinguish them from typical shocks. Perhaps more surprising, there was a burst of seismicity 230 km (140 mi) to the northwest of the M 6.4 a little over 6 hours later near the city of Mostar in Bosnia and Herzegovina, capped by a Mag 5.4 shock. This might be a coincidence, but if these two distant events are indeed related, it would have to be by the stresses carried by the seismic waves of the M 6.4, which dissipate within several minutes.

Could the Mag. 5.4 shock be a remotely triggered aftershock of the M 6.4? There is likely no smoking gun, but the possibility is nevertheless tantalizing.

A long history of large earthquakes

The high earthquake hazard of coastal Albania stems from tectonic compression of the crust that extends from Croatia south to Greece. The compression is evident in the contraction of the Earth’s surface measured by GPS, and by the long history of large earthquakes in the region. In fact, the southern Balkans are more seismically active than Italy.

Figure from Sevilgen et al. 2014 showing the ‘EMEC’ instrumental and historical earthquake catalog (Grünthal and Wahlström, 2012). The earthquake catalog extends to AD 1000; however, it is incomplete until about the past century, meaning that not all M≥5.5 quakes were recorded due to lack of seismometer coverage. But even when restricted to that time period (red shocks), the site of the 25 Nov 2019 quake is among the most active anywhere in the Balkans or Italy.

Blind thrust fault a likely culprit

The contraction has produced a series of thrust faults, only some of which come to the surface. Those that do not cut the Earth’s surface instead fold the overlying strata. Croatia’s coastal islands are one example of these folds, and one of these folds lies at the epicenter of the 26 Nov 2019 quake.

Koci et al. (2011) and Kastelic et al. (2016) identified active faults in the region for the European SHARE project using satellite imagery and field mapping (with inferred fault slip rates in black numerals), and they subsequently remapped the region (revised fault slip rates in red numerals; Sevilgen et al., 2014). One can see that thrust faults near the 26 Nov 2019 epicenter are about 75 km long with slip rates of ~1 mm/yr. That would mean that M~6.4 quakes on these faults would have mean inter-event times of roughly 500-1,000 years.

Amplified shaking on the coastal plains

The shaking produced by the Mag. 6.4 shock was almost certainly amplified in the weak, unconsolidated basins and coastal estuaries surrounding the epicenter. Temblor’s STAMP model shows amplification factors of 4-5 over the shaking that was experienced at bedrock sites, such as at the epicenter itself. Compounding the weak soil are water-saturated coastal plains, which are susceptible to liquefaction. This is where the soil turns to quicksand, causing buildings to sink or tilt. Sandblows and eruptions of artesian water often accompany shaking in such regions, compounding the damage.

Temblor’s STAMP high resolution (200 m) model of site amplification reveals that in Thumanë, Durres, and Lezhe, the shaking could have been severely amplified, contributing to the damage of weak buildings. Areas in black likely shook four times higher than those in yellow. The black areas are water-saturated coastal estuaries and plains that might also liquify when shaken violently, which can cause buildings to sink and tilt, rendering them a total loss. The fault on which the Mag. 6.4 quake struck is probably concealed by a growing fold.

Undoubtedly, emergency responders, geologists, and seismologists will learn more about this quake in the days to come. But what we can say now is that the hazard was not unforeseen.

References

Grünthal, G. and Wahlström, R. (2012): The European‐Mediterranean Earthquake Catalogue (EMEC) for the last millennium, Journal of Seismology, 16, 3, 535‐570, doi: 10.1007/s10950‐012‐9302‐y

Vanja Kastelic, Michele M.C. Carafa, and Francesco Visini (2016), Neotectonic deformation models for probabilistic seismic hazard: a study in the External Dinarides, Geophysical Journal International, 205, 1694–1709, https://doi.org/10.1093/gji/ggw106

R. Koci, N. Kuka, V. Kuk, K. Kuk, J. Mihaljevic, B. Glavatovic, H. Hrvatovic, I. Brlek, S. Kovacevic, S. Radovanovic, Z. Milutinovic, R. Salic (2011), Seismotectonic model as the OHAZ input, in Harmonization of Seismic Hazard Maps for the Western Balkan Countries, Closing Meeting Zagreb, 12-13 May 2011 (mihaljevic@seismo.co.me)

Volkan Sevilgen , R.A. Bennett , I. Brlek , Laurentiu Danciu , V. Kastelic , S. Kovacevic , C. Kreemer , K., Kuk , N. Kuka , Z. Milutinovic , S. Mustafa , B. Sket-Motnikar , Ross S. Stein , and L. Vucic (2014), BALKANS-OQ: A collaborative seismic hazard assessment of the Balkan countries using the OpenQuake software and the GEM Strain Rate Model, Second European Conference on Earthquake Engineering and Seismology, Istanbul, http://www.eaee.org/Media/Default/2ECCES/2ecces_esc/3276.pdf

See the full article here .

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

Please help promote STEM in your local schools.

Stem Education Coalition

Earthquake Alert

Earthquake Alert

Earthquake Network project

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

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

Get the app in the Google Play store.

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

Meet The Quake-Catcher Network

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

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

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

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

The primary project partners include:

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

The Earthquake Threat

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

Part of the Solution

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

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

System Goal

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

Current Status

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

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

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

Authorities

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

For More Information

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

Learn more about EEW Research

ShakeAlert Fact Sheet

ShakeAlert Implementation Plan

From temblor: “M=7.3 earthquake rattles Venezuela and the Caribbean”

From temblor

August 22, 2018
David Jacobson, M.Sc.

Port of Spain, the capital of Trinidad and Tobago sustained damage in yesterday’s M=7.3 earthquake in northeastern Venezuela.

A large earthquake causes damage but no fatalities

Yesterday, at just past 9:30 p.m. local time, a M=7.3 earthquake struck the northeastern coast of Venezuela. Fortunately, this quake occurred in a relatively remote area, and there are no reported deaths as of this morning. However, there is damage from the quake, including in Caracas, Venezuela’s capital, nearly 600 km (370 mi) away. Even though only light shaking was recorded in Caracas, according to the USGS ShakeMap, it was great enough to cause the top ten floors of an abandoned skyscraper to shift and lean precariously over the road far below. According to CNN, that area has been evacuated. Closer to the epicenter, in places such as Port of Spain, Trinidad and Tobago, additional structural damage has been observed in buildings.

This Temblor map shows the location of yesterday’s earthquake in northeastern Venezuela. Also visible on the left and right sides of the map respectively are Venezuela’s capital city of Caracas and Trinidad and Tobago’s capital Port of Spain.

A region marked by strike-slip activity

While seismic activity is not uncommon in this region, yesterday’s M=7.3 quake is much deeper, and had different motion than the majority of quakes that impact Venezuela. Northern Venezuela is marked by the boundary between the South American and Caribbean plates. In this location, plate motion is approximately 20 mm/yr, and typically results in right-lateral strike-slip earthquakes at shallow depths. However, yesterday’s earthquake was compressional in nature, and occurred at a depth of 123 km. Therefore, it did not occur on the plate boundary, but rather well beneath it.

Even though much of the seismicity in the region is dominated by the strike-slip plate boundary, the region is also subject to compression and some believe that off the northeastern coast of Venezuela there is an ancient, or not fully-formed subduction zone (Pindell et al., 2015). This zone, which Pindell et al. term the Proto-Caribbean Inversion Zone has the same rough orientation as the strike of yesterday’s earthquake. So, it at least seems possible that the event occurred on this structure, which could pose additional hazards for Venezuela and the southeastern Caribbean.

Regardless of what structure yesterday’s earthquake occurred on, what this event highlights is the seismic hazard of the region. This illustrates both that large earthquakes are possible, and that even weak to light shaking can cause significant damage to buildings not of the highest build quality, as was seen in Caracas. Therefore, it is not only important to know the seismic hazard of where you live, but whether or not your home or office is capable of withstanding shaking.

References
USGS
CNN
Jame L. Pindell, Lorcan Kennan, David Wright & Johan Erikson, Clastic domains of sandstones in central/eastern Venezuela, Trinidad, and Barbados: heavy mineral and tectonic constraints on provenance and palaeogeography, From James, K. H., Lorente, M. A. & Pindell, J. L. (eds) The Origin and Evolution of the Caribbean Plate. Geological Society, London, Special Publications, 328, 743–797

See the full article here .

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

Please help promote STEM in your local schools.

Stem Education Coalition

Earthquake Alert

Earthquake Alert

Earthquake Network project

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

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

Get the app in the Google Play store.

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

Meet The Quake-Catcher Network

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

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

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

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

The primary project partners include:

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

The Earthquake Threat

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

Part of the Solution

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

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

System Goal

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

Current Status

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

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

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

Authorities

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

For More Information

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

Learn more about EEW Research

ShakeAlert Fact Sheet

ShakeAlert Implementation Plan

From temblor: “Giant crack opens in East African Rift Valley”

temblor

April 3, 2018
David Jacobson

This photo shows a large crack that recently appeared in the East African Rift Valley. The crack, which is up to 50 feet deep and 65 feet wide significantly damaged a major road and destroyed homes. No image credit.

The East African Rift Valley is one of the most famous geologic regions on earth. Stretching for over 3,000 km from the Gulf of Aden in the north to Mozambique in the south, it marks where the African continent is being split into the Somali and Nubian plates. Scientists estimate that within 10 million years, the Somali plate will break off from the rest of Africa and a new ocean basin will form. Even though this is an extremely slow process, every once in a while, new crevices appear, highlighting the power of earth’s tectonic forces. Only recently, near the small town of Mai Mahiu, just west of Kenya’s capital of Nairobi, a large crack, 50 feet deep and 65 feet wide appeared, damaging a major road, and several houses.

A man takes a selfie in front of the large crack in the East African Rift following heavy rain. (Reuters/Thomas Mukoya)

This crack did not form overnight, but it did appear in a matter of moments

A crack of this magnitude does not form overnight. The rifting process in East Africa is taking place at a rate of approximately 0.25 inches per year, or in other words, unnoticeable to most. We also know from aerial imagery that this feature was present prior to this massive unveiling. In the Google Earth image below, a large linear feature, perfectly matching the orientation of the crack in the photo above, is clearly visible cutting across the landscape. So, what happened to make the crack appear all of a sudden? The answer is simple: rain.

This Google Earth image shows the location of the collapsed road near the town of Mai Mahiu, just east of Nairobi. This photo also appears to show evidence of the crack, which is pointed out by the red arrows. The linear feature appears to match the orientation of the crack in the photo above.

Over the last month, Kenya has experienced heavy rainfall, which has resulted in extensive flooding across much of East Africa. While flooding alone would not do this, much of the soil has volcanic ash from nearby Mt. Longonot (see below). Volcanic ash can be easily washed away, meaning when heavy rain came, the water followed the path of least resistance, revealing this crevice. According to reports from National Geographic, at least one resident narrowly escaped his house before it collapsed. For the time being, local news outlets are reporting that the crack is being filled in with concrete and rocks, as the Mai Mahiu-Narok road is a major transportation route in Kenya.

Scientists believe that erosion of soil rich in ash from nearby Mt. Longonot (shown above) is responsible for the appearance of the large crack in the East African Rift. (Photo by: David Jacobson)

Why is Africa Rifting?

This photo shows the East African Rift Valley in Tanzania. (Photo from: Shutterstock)

Earth’s tectonic plates are constantly in motion. As these plates move, they can slide next one another, like the San Andreas Fault, collide with one another forming mountain ranges like the Himalayas, or move apart from each other, which is what is happening in East Africa.

The tectonic plates of the world were mapped in 1996, USGS.

As the Somali plate slowly separates from the Nubian plate, the earth’s crust gets thinner. Even though this process is slow, eventually the crust gets too thin and ruptures, creating a rift valley. This is the first step in the continental breakup process. The figure below shows these plate boundaries in East Africa and highlight where Africa is breaking apart, illustrating where a new ocean basin may form. While we will not be around to see that, we can bear witness to some of the initial stages.

This figure shows the plate boundaries in East Africa as well as the approximate location of the newly-exposed crack. Scientists estimate that if the continental breakup process continues, in 10 million years, a new ocean basin will form where the Rift Valley is now. (James Wood and Alex Guth, Michigan Technological University. Basemap: Space Shuttle radar topography image by NASA)

References [sorry, no links.]
The Conversation
PBS
National Geographic
Quartz
Daily Nation

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

Earthquake Alert

Earthquake Alert

Earthquake Alert Network project

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

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

Get the app in the Google Play store.

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

Meet The Quake-Catcher Network

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

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

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

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

The primary project partners include:

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

The Earthquake Threat

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

Part of the Solution

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

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

System Goal

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

Current Status

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

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

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

Authorities

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

For More Information

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

Learn more about EEW Research

ShakeAlert Fact Sheet

ShakeAlert Implementation Plan

From temblor: “M=5.4 earthquake strikes the Philippines and shakes Manila”

temblor

May 26, 2017
David Jacobson

Manila, the capital city of the Philippines, experienced shaking in yesterday’s M=5.4 earthquake. (Photo from: angkulet.com)

Yesterday, at 10:27 p.m. local time, a M=5.4 earthquake struck the island of Luzon in the Philippines and was felt in the capital city of Manila, which is home to nearly 2 million people. On the USGS website, nearly 500 people reported feeling the quake, though we know many more actually felt it. According to the Philippine Institute of Volcanology and Seismology (PHIVOLCS), there are no reports of damage. Damage is also unlikely as the quake only caused light to moderate shaking. Despite the fact that the quake occurred at a depth of approximately 100 km, and was only a moderate magnitude, reports say that some people felt the quake for nearly 20 seconds in tall buildings.

The island of Luzon is the largest and most populated island in the Philippines, and is also very seismically active. To the west is the Manila trench, which is where the Sunda Plate subducts beneath the Philippine Sea Plate. To the east are both the East Luzon Trench and the Philippine Sea Trench, which are separated by a left-lateral transform boundary. The two subduction zones which bound the island mean that all of Luzon is susceptible to large earthquakes.

This Temblor map shows the main faults around the Philippines. The island of Luzon is flanked to the west by the Manila Trench and to the east by the Philippine Sea Trench. Additionally, this map shows the Valley Fault System, which poses a great threat to the capital city of Manila. (Philippines faults from G-EVER)

Yesterday’s earthquake occurred at a depth suggesting it was on or near the western subducting slab. However, based on the USGS focal mechanism the quake had extensional and strike-slip motion rather than compressional. The strike-slip component can be explained by understanding that because of the subduction zones on either side of the island, the southern part of Luzon is being sheared. Furthermore, from the Temblor image above, one can also see that the southern portion of the Manila Trench begins trending to the southeast. This means that due to prevailing plate motion vectors, this part of the subduction zone is likely a transform or oblique boundary. The extensional component is a bit more tricky given the compressional regime that the Philippines sits in. However, when the dip of a subducting slab changes, tensional cracks can form and extensional faulting can result. Therefore, based on the depth of this quake, this is a likely explanation.

In addition to large subduction zones flanking the island of Luzon, there are also a series of surface faults, including the Valley Fault System, which runs straight through Manila. While this fault has not ruptured recently, 4 times in the past 1,400 years, it represents a great seismic hazard to Manila since it is capable of M=7+ earthquakes.

Based on the Global Earthquake Activity Rate (GEAR) model, we can see what types of earthquakes the island of Luzon could expect. This model uses global strain rates and seismicity since 1977 to forecast the likely earthquake magnitude in your lifetime anywhere on earth. In the Temblor map below, one can see that in the area around yesterday’s earthquake, the likely magnitude is 7.0+, while for Manila, it is 6.75+. Therefore, while yesterday’s quake should not be considered surprising, this map does give an indication that large earthquakes in the Philippines are possible, and likely.

This Temblor map shows the Global Earthquake Activity Rate (GEAR) model for the Philippines. This model uses global strain rates and seismicity since 1977 to forecast the likely earthquake magnitude in your lifetime anywhere on earth. From this figure one can see that around the location of yesterday’s earthquake the likely magnitude is M=7.0, while around Manila it is M=6.75.

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 COSMOS- “Japanese volcano interrupted an earthquake: study”

COSMOS

21 October 2016
Amy Middleton

It looks like Mt Aso’s magma chamber stifled part of the magnitude-7.1 Kumamoto earthquake in April, but that stress might boost its activity, seismologists warn.

The largest active volcano in Japan, Mount Aso, may have put stopped a 7.1-magnitude earthquake in its tracks. STR / AFP / Getty Images

When an earthquake tore down a fault line in Japan in April this year, its destructive course may have been halted early thanks to a crater beneath a nearby volcano.

A day after the magnitude-7.1 Kumamoto earthquake struck Kyushu Island in southwest Japan, Japanese seismologists, led by Aiming Lin of Kyoto University, headed into the field to investigate its passage.

According to their paper published in Science today, the quake had torn through 40 kilometres of earth along the Hinagu–Futagawa Fault Zone, as well as a series of newly discovered faults, in close proximity to nearby Mt Aso – one of the world’s largest active volcanoes.

Although experts know there’s a relationship between volcano and earthquake activity, it’s a tricky interaction to study because examples don’t come up too often.

The proximity of this quake to Mt Aso presented a rare opportunity.

The researchers identified new faultlines cut into a 380-kilometre-wide crater that forms part of Mt Aso. Interestingly, the rupture that cut into the volcanic crater – also known as a caldera – terminated suddenly.

The cause of this interruption, the researchers suggest, was the magma chamber under the volcanic crater around three kilometres beneath the Aso caldera.

At the depth of the magma chamber, around six kilometres below the crater, the quake’s ruptures ceased, probably because the magma chamber’s extreme temperature (around 580 °C) sent the seismic pressure upwards instead of continuing its path.

“Magma is fluid so it absorbs stress,” says Lin.

“That’s why the damage – the co-seismic rupturing – shouldn’t travel any further.”

This change in pressure direction created a new series of stress fields beneath the active volcano.

Importantly, the researchers suggest the new ruptures under the caldera could potentially trigger an eruption of Mt Aso in the near future and they urge experts keep a close eye on its activity.

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

From Science Alert: “A SECOND fault line running parallel to San Andreas has just been identified”

Science Alert

And it might be holding everything together.

5 OCT 2016
BEC CREW

The San Andreas Fault. Credit: US Geological Survey

Just days after a cluster of more than 200 small earthquakes shook the Salton Sea area of Southern California, scientists have found evidence of a second fault line that runs parallel to the massive San Andreas Fault – one of the state’s most dangerous fault lines.

The new fault appears to run right through the 56-km-long Salton Sea in the Colorado Desert, to the west of the San Andreas Fault. Now that we know it’s there, seismologists will be forced to reassess earthquake risk models for the greater Los Angeles area.

“This previously unidentified fault represents a new hazard to the region and holds significant implications for fault models … and, consequently, models of ground-motion prediction and southern San Andreas Fault rupture scenarios,” the team from the Scripps Institution of Oceanography and the Nevada Seismological Laboratory reports.

Now known as the Salton Trough Fault, the newly mapped fault has been hidden for all this time because it’s submerged beneath the Salton Sea – a vast, salty rift lake that formed as a result of all the tectonic activity in the area.

The team had to use an array of instruments, including multi-channel seismic data, ocean-bottom seismometers, and a surveying method called light detection and ranging (LiDAR), to precisely map fault inside several sediment layers both in and surrounding the lakebed.

“The location of the fault in the eastern Salton Sea has made imaging it difficult, and there is no associated small seismic events, which is why the fault was not detected earlier,” says Scripps geologist Neal Driscoll.

Oddly enough, the fact that we now know there’s an extra fault line running parallel to the San Andreas Fault doesn’t necessarily mean the area is more prone to earthquakes than we originally thought.

It might actually solve the mystery of why the region has been experiencing LESS earthquakes than expected.

As the team explains, recent research has revealed that the region has experienced magnitude-7 earthquakes roughly every 175 to 200 years for the last 1,000 years.

But that’s not been the case more recently. In fact, a major rupture on the southern portion of the San Andreas Fault has not occurred in the last 300 years, and researchers think the region is long overdue for a major quake.

Now they have to figure out what role the Salton Trough Fault could have played in all that.

“The extended nature of time since the most recent earthquake on the Southern San Andreas has been puzzling to the earth sciences community,” said one of the Nevada team, seismologist Graham Kent.

“Based on the deformation patterns, this new fault has accommodated some of the strain from the larger San Andreas system, so without having a record of past earthquakes from this new fault, it’s really difficult to determine whether this fault interacts with the southern San Andreas Fault at depth or in time.”

A map of the new fault line, STF. Credit: Sahakian et. al.

On Monday morning, ominous rumblings started to emanate from deep underneath the Salton Sea, and then a ‘swarm’ of small earthquakes – three measuring above magnitude 4 – ruptured at the nearby Bombay Beach.

The ruptures continued for roughly 24 hours, with more than 200 small earthquakes having been recorded in the area.

These small earthquakes – or temblors – were not very severe, but this is just the third time since records began in 1932 that the area has experienced such an event. And this one had more earthquakes than both the 2001 and 2009 events.

The event caused the US Geological Survey to increase the estimated risk of a magnitude 7 or greater earthquake in the next week from to between 1 in 3,000 and 1 in 100. To put that in perspective, without any quake swarms, the average risk for the area sits at around 1 in 6,000.

Fortunately, the increased risk now appears to have passed, and according to the Los Angeles Times, California governor’s Office of Emergency Service just announced that the earthquake advisory period is now officially over.

Of course, for those living in the area, it’s cold comfort, because the southern San Andreas Fault is still “locked, loaded, and ready to go”. Let’s hope the discovery of the Salton Trough Fault will make it easier for seismologists to at least predict when that will happen.

The research has been published in the Bulletin of the Seismological Society of America.

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

From U Hawaii: “Probability of Aleutians mega-earthquake estimated”

University of Hawaii

May 13, 2016
Marcie Grabowski

The map showing the Aleutians with respect to Hawaiʻi. The red and yellow arcs indicate the sections of the Aleutian subduction zones considered in the probability analysis. Stars and dates indicate epicenters of prior 20th century great earthquakes (Mw > 8). (credit: Butler et al., 2016)

A team of researchers from the University of Hawaiʻi at Mānoa published* a study this week that estimated the probability of a magnitude 9+ earthquake in the Aleutian Islands—an event with sufficient power to create a mega-tsunami especially threatening to Hawaiʻi. In the next 50 years, they report, there is a 9 percent chance of such an event. An earlier State of Hawaiʻi report (PDF) (Table 6.12) has estimated the damage from such an event would be nearly $40 billion, with more than 300,000 people affected.

Earth’s crust is composed of numerous rocky plates. An earthquake occurs when two sections of crust suddenly slip past one another. The surface where they slip is called the fault, and the system of faults comprises a subduction zone. Hawaiʻi is especially vulnerable to a tsunami created by an earthquake in the subduction zone of the Aleutian Islands.

Back to basics

“Necessity is the mother of invention,” said Rhett Butler, lead author and geophysicist at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST). “Having no recorded history of mega tsunamis in Hawaiʻi, and given the tsunami threat to Hawaiʻi, we devised a model for magnitude 9 earthquake rates following upon the insightful work of David Burbidge** and others.”

Butler and co-authors Neil Frazer (SOEST) and William Templeton (now at Portland State University) created a numerical model based only upon the basics of plate tectonics: fault length and plate convergence rate, handling uncertainties in the data with Bayesian techniques.

Using the past to inform the future

To validate this model, the researchers utilized recorded histories and seismic/tsunami evidence related to the 5 largest earthquakes (greater than magnitude 9) since 1900 (Tohoku, 2011; Sumatra-Andaman, 2004; Alaska, 1964; Chile, 1960 and Kamchatka, 1952).

“These five events represent half of the seismic energy that has been released globally since 1900,” said Butler. “The events differed in details, but all of them generated great tsunamis that caused enormous destruction.”

To further refine the probability estimates, they took into account past (prior to recorded history) tsunamis—evidence of which is preserved in geological layers in coastal sediments, volcanic tephras, and archeological sites.

“We were surprised and pleased to see how well the model actually fit the paleotsunami data,” said Butler.

Mitigating the risk

Using the probability of occurrence, the researchers were able to annualize the risk. They report the chance of a magnitude 9 earthquake in the greater Aleutians is 9 percent ± 3 percent in the next 50 years. Hence the risk is 9 percent of $40 billion, or $3.6 billion. Annualized, this risk is about $72 million per year. Considering a worst-case location for Hawaiʻi limited to the Eastern Aleutian Islands, the chances are about 3.5 percent in the next 50 years, or about $30 million annualized risk. In making decisions regarding mitigation against this $30-$72 million risk, the state can now prioritize this hazard with other threats and needs.

The team is now considering ways to extend the analysis to smaller earthquakes, magnitude 7–8, around the Pacific.

The only well-documented paleotsunami deposit in Hawaiʻi from the 16th century is on Kauaʻi. The Makauwahi sinkhole, on the side of a hardened sand dune, is viewed toward the southeast from an apparent altitude of 342 m. Inset photos show two of the wall edges, indicating the edges of the sinkhole. The east wall, left, is 7.2 m above mean sea level and about 100 m from the ocean. Note for scale the people in the right image. (photo credits: R. Butler, left, Gerard Fryer, right, GoogleMaps, background and figure from Butler et al., 2014)

*Science paper:
Bayesian Probabilities for Mw 9.0+ Earthquakes in the Aleutian Islands from a Regionally Scaled Global Rate

**Science paper:
A Probabilistic Tsunami Hazard Assessment for Western Australia

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

System Overview

The University of Hawai‘i System includes 10 campuses and dozens of educational, training and research centers across the Hawaiian Islands. As the public system of higher education in Hawai‘i, UH offers opportunities as unique and diverse as our Island home.

The 10 UH campuses and educational centers on six Hawaiian Islands provide unique opportunities for both learning and recreation.

UH is the State’s leading engine for economic growth and diversification, stimulating the local economy with jobs, research and skilled workers.

From Science Alert: “Scientist says the San Andreas fault is ‘locked, loaded, and ready to roll’ “

Science Alert

5 MAY 2016
FIONA MACDONALD

That can’t be good.

Southern California Earthquake Centre

California’s San Andreas fault has been quiet for far too long and is overdue for a major earthquake, a leading geoscientist has announced. In a conference this week, the state was warned to prepare for a potential earthquake as strong as magnitude 8.0.

“The springs on the San Andreas system have been wound very, very tight. And the southern San Andreas fault, in particular, looks like it’s locked, loaded and ready to go,” said Thomas Jordan, director of the Southern California Earthquake Centre.

Jordan gave his warning in the keynote talk of the annual National Earthquake Conference in Long Beach, the Los Angeles Times reports.

Here’s why he’s so worried: research has shown that the Pacific plate is moving northwest relative to the North American plate at a rate of around 5 metres (16 feet) every 100 years – and that’s building up a whole lot of tension along the San Andreas fault line that needs to be relieved regularly.

But the last time southern California experienced a major shake-up was in 1857, when a magnitude 7.9 quake rupture almost 300 km (185 miles) between Monterey County and the San Gabriel Mountains.

Further south, areas of the fault line have been quiet even longer, with San Bernardino county not moving substantially since 1812, and the region near the Salton Sea remaining still since the late 1600s.

All of this means that there’s a lot of tension underneath California right now. Last year, Jordan’s team found there’s a 7 percent chance the state will experience a magnitude 8.0 quake in the next three decades.

And that’s a big problem. Back in 2008, a US Geological Survey report* found that a magnitude 7.8 earthquake on the southern San Andreas fault could cause more than 1,800 deaths, 50,000 injuries, US$200 billion in damage, and long-lasting infrastructure disruptions – such as six months of compromised sewer systems and ongoing wildfires.

Even though Los Angeles isn’t on the San Andreas fault line, simulations by the Southern California Earthquake Centre show that the shaking would quickly spread there:

Access mp4 video here .

According to their modelling, that size earthquake could cause shaking for nearly 2 minutes, said Jordan, with the strongest activity in the Coachella Valley, Inland Empire and Antelope Valley.

The reason Los Angeles is at so much risk is because it’s built over a sedimentary basin, and the seismic waves spread and get trapped there to cause more extreme and longer-lasting shaking. As you can see in the magnitude 8.0 simulation:

Access mp4 video here .

While Jordan praised recent initiatives to earthquake retrofit buildings in LA, he warned that the rest of the state needs to get ready for the next big one, by making residents more aware of ways to stay safe during an earthquake and when and how to evacuate.

“We are fortunate that seismic activity in California has been relatively low over the past century,” Jordan explained last year. “But we know that tectonic forces are continually tightening the springs of the San Andreas fault system, making big quakes inevitable.”

*Science paper
The ShakeOut Scenario

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

From CNN: “Ecuador earthquake: 77 killed, hundreds injured”

CNN

April 17, 2016
Faith Karimi and Steve Almasy, CNN

A major earthquake hit Ecuador’s central coast, killing at least 77 people as it buckled homes and knocked out power in a city hundreds of miles away, authorities said.
The magnitude-7.8 earthquake struck Saturday night, Vice President Jorge Glas said in a televised address.

Nearly 600 people were injured, he said, adding that the death toll is expected to go up as more information comes in.

A state of emergency is in effect for six provinces, but Glas urged those who left their homes in coastal areas to return, as the tsunami alert had been lifted.
Provinces under a state of emergency are Guayas, Manabi, Santo Domingo, Los Rios, Esmeraldas and Galapagos.

Nightlife venues closed

Hours after the earthquake, the nation’s soccer federation said it has suspended the remaining matches of the current round of the Ecuadorean championship.
The interior ministry also ordered all nightlife venues in affected areas closed for the next 72 hours.
All mobile operators are allowing free text messages for customers to reach out to loved ones in Manabi and Esmeraldas provinces, the vice president said.
In a race to help residents, Ecuador deployed 10,000 soldiers and 3,500 police officers to the affected areas, he said.
The tremor was centered 27 kilometers (16.8 miles) southeast of the coastal town of Muisne, according to the U.S. Geological Survey.
It’s the deadliest earthquake to hit the nation since March 1987, when a 7.2-magnitude tremblor killed 1,000 people, according to the USGS.

Body recovered

About 300 miles away in Guayaquil, the nation’s most populous city, emergency officials recovered one body from the scene of a bridge collapse, police told local media.

Elsewhere in the city of 2 million people, the earthquake left shoppers shaken. Video from a store showed kitchen utensils swinging back and forth as some items tumbled off shelves.
Some areas in the city lost power.
There were no immediate reports of damage or injuries in the capital of Quito, 173 kilometers (108 miles) from the epicenter of the earthquake.
The Pacific Tsunami Warning Center said the tsunami threat following the earthquake has “mostly passed.”
An earlier warning for other nations with coastlines on the Pacific was canceled.

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

From Eos: “Tiny Accelerometers Create Europe’s First Urban Seismic Network”

Eos

3.17.16
Antonino D’Alessandro

The system, under development in Acireale, Italy, could be used to monitor earthquakes in real time and help rescue workers focus efforts where they’re needed most.

A view from Piazza Duomo, showing the dome of the Cathedral of Acireale (left) and the Basilica of Saints Peter and Paul (right) in Acireale, Italy. Scientists hope that a new urban seismic network will help protect people in and around these and other places in the city by letting officials know where to concentrate rescue efforts should an earthquake strike. Credit: Antonino D’Allesandro

When a strong earthquake hits an urban area, prompt rescue operations can minimize the number of victims. Logically, the probability of saving a human trapped under debris or injured during the course of a disaster decreases exponentially as function of time, vanishing almost completely after about few hours. The Tokyo Fire Fighting Department Planning Section [2002] has quantified this further, stating that rescue within 3 hours is desirable and survival rate is drastically lower after 72 hours.

Past disasters—like the magnitude 6.6 quake that struck Iran on 26 December 2003—support this assessment. As a result of that earthquake, more than 43,000 people died, and only 30 were saved, despite the intervention of 1600 rescuers from 43 nations. This tragic outcome is likely related to the fact that many rescuers didn’t arrive until after 3 days.

The impact of a strong earthquake on an urban center can be considerably reduced by an efficient emergency management center, through timely and targeted actions immediately following the quake. A real-time urban seismic network—sensors laid out in a grid through a city—could help emergency management centers by providing immediate alert and postearthquake information summarized in maps of ground motion.

Researchers are using new technological advances to develop one such urban seismic network in Acireale, Italy. The network will not use traditional seismometers; rather, they will harness the less expensive technology of accelerometers.

An accelerometer designed by the Archimedes Automated Assembly Planning Project at Sandia National Laboratory.

Once operational, it will be the first urban seismic network in Europe.

Goals of an Urban Seismic Network

Urban seismic networks allow the disaster’s first responders to manage available resources, such as personnel and equipment needed to rescue people. Rescue operations and verification of damage to buildings could then be carried out according to a logical priority according to where the highest shaking was measured by the seismic network. Such an approach would minimize secondary effects induced by an earthquake and allow officials to protect critical infrastructure, thereby mitigating the economic and social costs of the earthquake.

Accelerometers to the Rescue

The high costs associated with the construction and installation of traditional seismic stations has made it nearly impossible to realize a true seismic network on an urban scale. However, recent technological developments in the field of microelectromechanical systems (MEMS) sensors, which can be configured to detect minute accelerations, may allow scientists to create an urban seismic network at low cost.

The internal devices that will constitute the MEMS accelerometric stations: the sensor, single-board computer, and GPS are manufactured by Phidgets Inc.

MEMS sensors are a set of highly miniaturized devices that receive information from the environment and translate physical quantities they sense into electrical impulses. Depending on how the sensors are configured, they can measure phenomena of various kinds: mechanical (sound, acceleration, and pressure), thermal (temperature and heat flux), biological (cell potential), chemical (pH), optical (intensity of light radiation and spectroscopy), and magnetic (intensity of flow). The MEMS devices that will be used in the project integrate a three-axis accelerometer, which can measure both constant accelerations (usable as a tilt sensor) and those that vary in time (used to measure the oscillation induced by an earthquake).

In the 1990s, MEMS sensors revolutionized the automotive airbag system and are today widely used in laptops, games controllers, drones, and mobile phones. When configured to measure ground shaking, the sensitivity and the dynamic range of these sensors are high enough to allow the researchers to record earthquakes of moderate magnitude even at a distance of several tens of kilometers [D’Alessandro and D’Anna, 2003; Evans et al., 2014]. Because of their low cost and their small size, MEMS accelerometers could be easily installed in urban areas to achieve a seismic network with a high density of measuring points.

In the past decade, a number of research institutes that focus on geophysics and seismology have shown interest in this promising technology. In California and Japan, scientists are developing networks consisting entirely of MEMS sensors. These include the Quake-Catcher Network, managed by Stanford University [Cochran et al., 2009; Chung et al., 2011; Kohler et al., 2013]; the Community Seismic Network, managed by the California Institute of Technology [Clayton et al., 2011; Kohler et al., 2013]; and the Home Seismometer Network, managed by the Japan Meteorological Agency [Horiuchi et al., 2009].
First European Urban Seismic Network

In September 2015, the Italian Ministry of Education, University and Research funded a 3-year project to create the first European urban seismic network using MEMS technology. The project is called Monitoring of Earthquakes through MEMS Sensors (MEMS project).

We chose the municipality of Acireale, Italy, an urban area particularly vulnerable to earthquake hazards [Azzaro et al., 2010, 2013], as a pilot site for the MEMS project. Acireale is located on the southeastern slopes of Sicily’s Etna volcano and is vulnerable to damage from tectonic and volcanic earthquakes.

Founded in the 14th century, Acireale contains many seismically vulnerable buildings of historical and cultural value. In the past 2 centuries, more than 190 damaging earthquakes have occurred in the Etna region, almost 1 per year. This includes an earthquake sequence that began with a main shock on 29 October 2002—following this magnitude 4.4 event, more than 400 buildings in Acireale were declared uninhabitable [Azzaro et al., 2010].

We aim to develop an urban seismic network comprising about 200 MEMS stations. Each station will consist of a three-axis digital MEMS accelerometer connected to a computer for on-site signals preprocessing. Each station will be supplied with a GPS for time synchronization and an Internet connection for data transmission to a processing center. Should an earthquake cause a power outage, the station can function autonomously for about 2 hours.

The MEMS stations will be located mainly inside buildings characterized by high vulnerability (old buildings that weren’t built to withstand high shaking) and high flux of people moving in and out, such as schools, hospitals, public buildings, and places of worship. The geometry of the network will be designed to create homogeneous coverage of the urban center, with a high enough density of stations in the vicinity of the well-known faults.

The network’s success will depend on our ability to implement algorithms able to prevent false alarms. Such algorithms will allow the creation of a shaking map only if a significant percentage of the MEMS stations have simultaneously detected a shaking event—if shaking is human made (e.g., an explosion), only the nearest stations would detect it, but an earthquake would be recorded by many stations. Automatic detection of patterns in waveforms that signal a specific seismic source will also be helpful.

What Can We Learn?

If all goes well, the network will be operational by the end of 2017. The seismic waveforms captured by the sensors will be processed in real time to identify several shaking parameters that will be used to create shake maps at the urban scale. The earthquake waveforms collected by the network will also be used to reconstruct the movement along the faults that caused the earthquakes to map seismic hazards and risks on a fine scale for the area covered.

The system could be used to implement a site-specific earthquake early warning system [Horiuchi et al., 2009]. Such a system could enhance the safety margin of specific critical engineered systems—such as energy plants or high-speed railway networks—in real time, mitigating the seismic risk by triggering automatic actions that aim to shelter people from exposure to shaking.

If successful, the MEMS project could provide a useful tool to reduce the seismic risk by increasing the safety of the population of the urban area covered by the network. Such a system could be quickly extended to other areas of high seismic risk, revolutionizing how communities monitor earthquakes. Communities would no longer need to focus on the characterization of earthquakes in terms of focus parameters (e.g., hypocenter and magnitude). Instead, networks like the MEMS project would characterize shaking by direct measurements of how shaking affects a city, neighborhood by neighborhood.

References

Azzaro, R., C. F. Carocci, M. Maugeri, and A. Torrisi (2010), Microzonazione sismica del versante orientale dell’Etna: Studi di primo livello, report, 184 pp., Le Nove Muse Editrice, Rome.

Azzaro, R., S. D’Amico, L. Peruzza, and T. Tuvè (2013), Probabilistic seismic hazard at Mt. Etna (Italy): The contribution of local fault activity in mid-term assessment, J. Volcanol. Geotherm. Res., 251, 158–169, doi:10.1016/j.jvolgeores.2012.06.005.

Chung, A. I., C. Neighbors, A. Belmonte, M. Miller, H. H. Sepulveda, C. Christensen, R. S. Jakka, E. S. Cochran, and J. F. Lawrence (2011), The Quake-Catcher Network rapid aftershock mobilization program following the 2010 M 8.8 Maule, Chile earthquake, Seismol. Res. Lett., 82(4), 526–532, doi:10.1785/gssrl.82.4.526.

Clayton, R. W., et al. (2011). Community Seismic Network, Ann. Geophys., 54(6), 738–747, doi:10.4401/ag-5269.

Cochran, E. S., J. F. Lawrence, C. Christensen, and R. S. Jakka (2009), The Quake-Catcher Network: Citizen science expanding seismic horizons, Seismol. Res. Lett., 80(1), 26–30, doi:10.1785/gssrl.80.1.26.

D’Alessandro, A., and G. D’Anna (2003), Suitability of low cost 3 axes MEMS accelerometer in strong motion seismology: Tests on the LIS331DLH (iPhone) accelerometer, Bull. Seismol. Soc. Am., 103, 2906–2913, doi:10.1785/0120120287.

Evans, J. R., R. M. Allen, A. I. Chung, E. S. Cochran, R. Guy, M. Hellweg, and J. F. Lawrence (2014), Performance of several low-cost accelerometers, Seismol. Res. Lett., 85, 147–158, doi:10.1785/0220130091.

Horiuchi, S., Y. Horiuchi, S. Yamamoto, H. Nakamura, C. Wu, P. A. Rydelek, and M. Kachi (2009), Home seismometer for earthquake early warning, Geophys. Res. Lett., 36, L00B04, doi:10.1029/2008GL036572.

Kohler, M. D., T. H. Heaton, and M.-H. Cheng (2013), The Community Seismic Network and Quake-Catcher Network: Enabling structural health monitoring through instrumentation by community participants, Proc. SPIE, 8692, 86923X, doi:10.1117/12.2010306.

Tokyo Fire Fighting Department Planning Section (2002), New Fire Fighting Strategies, Tokyo Horei, Tokyo.
Author Information

Antonino D’Alessandro, Istituto Nazione di Geofisica e Vulcanologia, Rome, Italy; email: antonino.dalessandro@ingv.it

Citation: D’Alessandro, A. (2016), Tiny accelerometers create Europe’s first urban seismic network, Eos, 97, doi:10.1029/2016EO048403. Published on 17 March 2016.

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