Aftershocks of the 2018 Anchorage earthquake continue in Southcentral Alaska

New ground motion sensors installed across Eagle River and the Mat-Su valley will help...
New ground motion sensors installed across Eagle River and the Mat-Su valley will help scientists with hazard assessment tasks to help Alaska better prepare for earthquakes.(Alaska Earthquake Center)
Published: Mar. 2, 2021 at 6:00 PM AKST
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FAIRBANKS, Alaska (KTVF) -Last Saturday morning an Earthquake was felt 10 miles north of downtown Anchorage, near Point MacKenzie. Dera Merz, Field Technician at the Alaska Earthquake Center details this quake’s relationship to the 2018 earthquake which caused widespread damage across Southcentral Alaska.

“It was a magnitude 5.3 earthquake on Saturday, and it was in fact an aftershock of the 2018 magnitude 7.1 earthquake. These aftershocks are still earthquakes, and they’re defined by two characteristics. Basically that being the location that it occurs in, and the timing after the main shock event,” said Merz.

According to Merz the epicenter of Saturday’s quake was right in the rupture zone where the original 7.1 magnitude earthquake occurred. While it’s effects are still being felt years later, the aftershocks of the 2018 quakes are diminishing.

“They wont last forever, these aftershocks. They definitely are, if you look at the statistics and how many are occurring on a day to day basis now, it’s a lot less than what was happening a year ago even. So they continue to decrease over time.”

Last week new ground motion sensors were installed across Eagle River and the Matanuska Valley regions as part of a collaboration between the University of Alaska Fairbanks Geophysical Institute, and the Engineering Department at the University of Alaska Anchorage. These new sensors are specialized for measuring the impacts of larger earthquakes, and won’t go offline during intense shaking.

“These sites are important for a number of different reasons. Firstly being during the 2018 earthquake there was quite a bit more structural damage in Eagle River and Mat-Su, compared to that in Anchorage. So these new sensors will help scientists determine if the ground is shaking more in that area and why,” Said Merz.

According to Merz this new data will help in allowing the Alaska Earthquake Center to determine whether the increased damage in these areas was due to the makeup of the ground itself, or due to the buildings in the region. The data from these sensors will be used in hazard assessments, assessing infrastructure, updating building codes, and emergency planning.

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