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Rupture Process of the 26 May 2019 M w 8.0 Northern Peru Intermediate‐Depth Earthquake and Insights Into Its Mechanism
Author(s) -
Liu Wei,
Yao Huajian
Publication year - 2020
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 - 10.1029/2020gl087167
Subject(s) - geology , slab , seismology , subduction , focal mechanism , earthquake rupture , slip (aerodynamics) , slab window , fault (geology) , tectonics , geophysics , oceanic crust , physics , thermodynamics
Abstract In the Nazca‐South American subduction zone, the subducted slab is flattened beneath northern Andes, called the Peruvian flat slab. The 2019 M w 8.0 northern Peru intermediate‐depth normal‐faulting earthquake occurred at the leading edge of the Peruvian flat slab, where the slab rebends and sinks into greater depths. Here we investigate this earthquake by back projection analysis and finite fault inversion using seismic waveforms at teleseismic distances. The rupture process indicates that this earthquake ruptured mainly along strike (353°) ~150 km north‐northwestward within ~55 s (average rupture velocity ~2.7 km/s), resulting in two major slip areas with three high slip rate areas, which are consistent with three high‐frequency energy radiation subevents. Our study suggests that such a heterogeneous rupture may be caused by slab bending forces and dehydration embrittlement associated with morphology of the slab.