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2020 M7.8 Simeonof Earthquake and M7.6 aftershock

The waveform modeling suggests that the M7.8 mainshock event had a thrust mechanism typical of a subduction zone interface event. The ruptured fault extends over an area of about 120 miles by 60 miles (200 km by 100 km). Preliminary finite fault inversions indicate that the maximum slip along the surface of the fault was on the order of 3-4 m.

The waveform modeling for the M7.6 aftershock suggests the event had more of a strike-slip mechanism. Preliminary finite fault inversions suggest a rupture that is either in the subducting OR overriding plate, not at the plate interface. The aftershock pattern seems to agree with a NNW trending fault.

We will update this page as the sequence unfolds.

Last Modified: April 29, 2022