Premium
The 2018 M W 7.9 Gulf of Alaska Earthquake: Multiple Fault Rupture in the Pacific Plate
Author(s) -
Lay Thorne,
Ye Lingling,
Bai Yefei,
Cheung Kwok Fai,
Kanamori Hiroo
Publication year - 2018
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 - 10.1029/2018gl079813
Subject(s) - intraplate earthquake , seismology , geology , aftershock , subduction , seismic gap , fault (geology) , induced seismicity , terrane , slip (aerodynamics) , interplate earthquake , north american plate , moment magnitude scale , pacific plate , seismic moment , tectonics , geometry , scaling , physics , mathematics , thermodynamics
A major ( M W 7.9) intraplate earthquake ruptured the Pacific plate seaward of the Alaska subduction zone near Kodiak Island on 23 January 2018. The aftershock seismicity is diffuse, with both NNW‐ and ENE‐trending distributions, while long‐period point source moment tensors have near‐horizontal compressional and tensional principal strain axes and significant non‐double‐couple components. Backprojections from three large‐aperture networks indicate sources of short‐period radiation not aligned with the best double‐couple fault planes. A suite of finite‐fault rupture models with one to four faults was considered, and a four‐fault model, dominated by right‐lateral slip on an SSE trending, westward‐dipping fault, is compatible with most seismic, GPS, and tsunami data. However, the precise geometry, timing, and slip distribution of the complex set of faults is not well resolved. The sequence appears to be the result of intraplate stresses influenced by slab pull, the 1964 Alaska earthquake, and collision of the Yakutat terrane in northeastern Alaska.