Tsunamis caused by submarine (below water) and subaerial (above the water) landslides are a serious hazard in bays and fjords of coastal Alaska, particularly in Southeast and South-central Alaska.
During 2019-2020, the Alaska Earthquake Center underwent an unprecedented expansion of our permanent seismic monitoring network. We were able to achieve it by acquiring 96 of 158 temporary USArray sites in Alaska.
On October 19, 2020 a magnitude 7.6 earthquake shook the ground in the vicinity of the July 22, 2020 M7.8 Simeonof earthquake aftershock region (Figure 1).
Large earthquakes, like the recent M7.8 in Alaska, can be seen at seismometers around the world! When an earthquake occurs, seismic energy travels in all directions, much like ripples in a pond.
This evening’s M7.8 earthquake [7/21/20, 10:12 PM AKDT] occurred on the well-known subduction zone interface off the Alaska Peninsula. Strong shaking has been reported from Perryville and Sand Point to King Cove and Cold Bay.
We use the phrase “magnitude of completeness” often when referring to our understanding of seismicity in a region or following a sequence of earthquakes. This value is a simplistic assessment of a catalog of earthquakes.
“As far as earthquakes go, for everyone in Alaska, there is someone looking out for you 24/7,” said Ken Macpherson, who manages the Alaska Earthquake Center’s data analyst team.
