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Seismic evidence of nonlinear crustal deformation during a large slow slip event in Mexico
Author(s) -
Rivet Diane,
Campillo Michel,
Shapiro Nikolai M.,
CruzAtienza Victor,
Radiguet Mathilde,
Cotte Nathalie,
Kostoglodov Vladimir
Publication year - 2011
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 - 10.1029/2011gl047151
Subject(s) - geology , seismology , crust , slip (aerodynamics) , amplitude , perturbation (astronomy) , seismic wave , deformation (meteorology) , seismic velocity , nonlinear system , strain rate , geophysics , geodesy , physics , oceanography , quantum mechanics , thermodynamics
Repeated cross‐correlations of ambient seismic noise indicate a long‐term seismic velocity change associated with the 2006 M7.5 slow‐slip event (SSE) in the Guerrero region, Mexico. Because the SSE does not radiate seismic waves, the measured velocity change cannot be associated with the response of superficial soil layers to strong shaking as observed for regular earthquakes. The perturbation observed maximized at periods between 7 s and 17 s, which correspond to surface waves with sensitivity to the upper and middle crust. The amplitude of the relative velocity change (∼10 −3 ) was much larger than the volumetric deformation (∼10 −6 ) at the depths probed (∼5–20 km). Moreover, the time dependence of the velocity perturbation indicated that it was related to the strain rate rather than the strain itself. This suggests that during strong slow‐slip events, the deformation of the overlying crust shows significant nonlinear elastic behavior.