Intraslab Deformation in the 30 November 2018 Anchorage, Alaska Mw 7.0 Earthquake

Date: 4/26/2019

Time: 06:00 PM

Room: Grand Ballroom

On 30 November 2018, Anchorage, Alaska was strongly shaken by an M_W 7.0 earthquake that ruptured within the underthrust Pacific plate at a depth of from 45 to 65 km. Ground failures occurred in saturated lowlands filled with sediments, producing notable road damage, but there was limited structural damage in Anchorage, only ~12 km south of the epicenter. The earthquake had a normal faulting geometry with a shallowly dipping east-west tension axis indicating intraslab deformation, likely between the underthrust Yakutat terrane and adjacent Pacific seafloor. Separate and joint inversions of teleseismic P and SH waves, regional strong ground motions, and GPS static displacements provide a weak preference for a westward steeply-dipping rupture plane with up to 2 m of slip distributed over a single slip patch with dimensions of 20 km x 20 km. The rupture duration was ~12 s. Aftershocks occur at shallower depths than the mainshock slip zone.

Presenting Author: Chengli Liu

Authors