From temblor: “M=4.4 earthquake highlights in progress seismic swarm in Yellowstone National Park”

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temblor

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The western part of Yellowstone National Park experienced a M=4.4 earthquake yesterday evening. This quake is part of a seismic swarm which began on June 12. According to the University of Utah, seismic swarms make up approximately 50% of the seismicity around the Yellowstone region. (Photo from: visitmt.com)

Yesterday, at 6:48 p.m. local time, a M=4.4 earthquake struck the western edge of Yellowstone National Park in Wyoming. According to a press release from the University of Utah, the quake was felt throughout the national park as well as in the nearby towns of West Yellowstone and Gardiner. On the USGS website, only 97 people reported feeling the quake, though the number that actually felt it is likely much higher. So far, there are no reports of damage, which is not surprising given the quake’s magnitude, which only registered light shaking near the epicenter, based on the USGS ShakeMap.

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This Temblor map shows the location of yesterday’s M=4.4 earthquake in the western part of Yellowstone National Park. This earthquake is part of a larger swarm, which began on June 12. Also in this figure is the location of the 1959 M=7.3 Hebgen Lake earthquake.

According to the University of Utah, this M=4.4 earthquake is part of a swarm that began on June 12, that has included 30 M=2+ earthquakes, and four M=3+ earthquakes, including the one yesterday. They also point out that swarms like this are extremely common in the Yellowstone region, and comprise approximately 50% of the seismicity. While there are mapped faults around the location of this active swarm, based on the northwest trend in the seismicity, and a focal mechanism produced by Bob Herrmann of St. Louis University, this quake appears to have occurred on a left-lateral strike-slip fault which connects the east-west-trending extensional faults in the region. It should also be pointed out that this M=4.4 quake is the largest to strike the area since 2014, when there was a M=4.8.

Seismic activity around Yellowstone is extremely common and is caused by a variety of factors. Some of the smaller earthquakes are a result of rising and moving magma beneath the surface. However, Yellowstone is unlikely to experience a large earthquake because the hot magma beneath the surface causes the bedrock to behave more ductile, meaning it is less likely to rupture. While large earthquakes within the park are unlikely, the region is highly sensitive to remote earthquakes. What this means is that seismic waves from earthquakes hundreds of kilometers away can slightly destabilize the volcanic and hydrothermal systems, resulting in small earthquakes and hydrothermal eruptions.

The area around today’s small-moderate earthquake is also of interest as it is only 15-20 km from the epicenter of the 1959 M=7.3 Hebgen Lake earthquake. This earthquake killed 28 people and resulted in millions of dollars worth of damage. The majority of these fatalities were the result of a massive landslide triggered by the shaking. Therefore, while rare, large earthquakes can occur just outside of Yellowstone. Based on the Global Earthquake Activity Rate (GEAR) model, which is available in Temblor we can see that yesterday’s M=4.4 earthquake in Yellowstone should not be considered surprising, given the region is susceptible to M=5.25+ quakes. This model uses seismicity since 1977 and global strain rates to forecast what the likely earthquake magnitude is in your lifetime anywhere on earth. What we can also see from this model is that the M=7.2 Hebgen Lake earthquake just to the west of yesterday’s shock was an extremely rare and surprising event. Should the characteristics of this ongoing swarm in Yellowstone National Park change, we will update this post.

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This Temblor map shows the Global Earthquake Activity Rate (GEAR) model for the area around Yellowstone National Park. What is evident from this map is that the M=4.4 earthquake should not be considered surprising, given the area is susceptible to M=5.25+ quakes. The GEAR model uses seismicity since 1977 and global strain rates to forecast the likely earthquake magnitude in your lifetime anywhere on earth.

References
University of Utah Seismograph Stations
USGS
Bob Herrmann (St. Louis University)
Robert B. Smith (University of Utah)
Jamie Mark Farrell (University of Utah)

See the full article here .

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

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

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

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

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

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

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

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

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