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Earthquake Depth Phase Extraction With P Wave Autocorrelation Provides Insight Into Mechanisms of Intermediate‐Depth Earthquakes
Author(s) -
Fang Hongjian,
Hilst Robert D.
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 - 10.1029/2019gl085062
Subject(s) - geology , seismology , subduction , slab , autocorrelation , magnitude (astronomy) , geophysics , tectonics , physics , mathematics , astronomy , statistics
Abstract Constraining the mechanism of earthquakes in subduction zones requires adequate estimates of source location and near‐source elastic properties. In this study, we propose a P wave autocorrelation‐based method to extract depth phase energy from teleseismic earthquakes with moment magnitude down to 4.0. We apply the method to improve location estimates of intermediate‐depth earthquakes in the Japan and northern Chile subduction zones, which represent so‐called cold and warm slabs, respectively, and which are both marked by double seismic zones. A positive correlation of slab age and double‐seismic‐zone width validates a thermally controlled model of slab morphology. The negative to normal differential times (and, thus, low or normal Vp/Vs) of the deep parts of the double seismic zones suggest that the intermediate‐depth earthquakes considered here are not due to dehydration.