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.
Seismic activity near Mt. Ogden and Wright Glacier, about 40 miles east of Juneau, picked up starting on July 10, 2020 (Figure 1).
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.