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Intraslab Deformation in the 30 November 2018 Anchorage, Alaska, M W 7.1 Earthquake
Author(s) -
Liu Chengli,
Lay Thorne,
Xie Zujun,
Xiong Xiong
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl082041
Subject(s) - epicenter , geology , aftershock , seismology , terrane , slip (aerodynamics) , earthquake rupture , seafloor spreading , foreshock , tectonics , geophysics , fault (geology) , physics , thermodynamics
Abstract Anchorage, Alaska, was strongly shaken on 30 November 2018 by an M W 7.1 earthquake that ruptured within the underthrust Pacific plate at depths 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 has 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 × 20 km. The ~12 s long rupture expanded northward. Aftershocks occur at shallower depths than the mainshock slip zone.