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Spatiotemporal variations of characteristic repeating earthquake sequences along the Middle America Trench in Mexico
Author(s) -
Dominguez Luis A.,
Taira Taka'aki,
Santoyo Miguel A.
Publication year - 2016
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2016jb013242
Subject(s) - seismology , subduction , geology , trench , waveform , slip (aerodynamics) , intraplate earthquake , slow earthquake , interplate earthquake , geodesy , tectonics , physics , chemistry , organic chemistry , layer (electronics) , thermodynamics , quantum mechanics , voltage
Searching for repeating earthquakes allows the examination of spatiotemporal variation of slip budget in the subduction of the Cocos plate in the Guerrero‐Oaxaca region of Mexico. As different transient phenomena continuously load and unload stresses around asperities in an area where megathrust earthquakes nucleate, repeating earthquakes act as track markers for slip on the plate interface. We systematically examined 14 years of waveform records from 2001 through 2014 to identify repeating earthquakes along the subducting segment of the Cocos plate. An analysis of waveform similarity resulted in a significant number (224) of earthquake sequences with highly correlated waveforms (correlation coefficient cc ≥ 0.95 and spectral coherency coh ≥ 0.95). The reported set of correlated waveforms shows a well‐defined clustering in space and substantial temporal variability. We find a significant increase of repeating earthquake activity after the 20 March 2012 Ometepec ( M w 7.4) and 18 April 2014 Tecpan ( M w 7.2) earthquakes as a result of the postseismic relaxation. In contrast, the rupture zone of the 1985 ( M w 8.1) Michoacán earthquake is completely devoid of repeating sequences, suggesting a strongly coupled segment. Examining the temporal behavior of repeating earthquake activity provides a new tool to better understand how creeping of the subduction thrust controls stress release and postseismic relaxation.