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Post-seismic viscoelastic deformation and stress transfer after the 1960 M9.5 Valdivia, Chile earthquake: effects on the 2010 M8.8 Maule, Chile earthquake

Post-seismic viscoelastic deformation and stress transfer after the 1960 M9.5 Valdivia, Chile... After the 1960 M9.5 Valdivia, Chile earthquake, three types of geodetic observations were made during four time periods at nearby locations. These post-seismic observations were previously explained by post-seismic afterslip on the downdip extension of the 1960 rupture plane. In this study, we demonstrate that the post-seismic observations can be explained alternatively by volumetric viscoelastic relaxation of the asthenosphere mantle. In searching for the best-fitting viscosity model, we invert for two variables, the thickness of the elastic lithosphere, He, and the effective Maxwell decay time of the asthenosphere mantle, TM, assuming a 100-km-thick asthenosphere mantle. The best solutions to fit the observations in four sequential time periods, 19601964, 19601968, 19651973 and 19802010, each yield a similar He value of about 65km but significantly increasing TM values of 0.7, 6, 10 and 80 yr, respectively. We calculate the corresponding viscoelastic Coulomb stress increase since 1960 on the future rupture plane of the 2010 M8.8 Maule, Chile earthquake. The calculated viscoelastic stress increase on the 2010 rupture plane varies gradually from 13.1 bars at the southern end to 0.1 bars at the northern end. In contrast, the stress increase caused by an afterslip model has a similar spatial distribution but slightly smaller values of 0.13.2 bars on the 2010 rupture plane. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Geophysical Journal International Oxford University Press

Post-seismic viscoelastic deformation and stress transfer after the 1960 M9.5 Valdivia, Chile earthquake: effects on the 2010 M8.8 Maule, Chile earthquake

Ding, Min; Lin, Jian
Geophysical Journal International , Volume 197 (2) – May 1, 2014
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References (28)

Publisher
Oxford University Press
Copyright
The Authors 2014. Published by Oxford University Press on behalf of The Royal Astronomical Society.
Subject
Geodynamics and tectonics
ISSN
0956-540X
eISSN
1365-246X
DOI
10.1093/gji/ggu048
Publisher site
See Article on Publisher Site

Abstract

After the 1960 M9.5 Valdivia, Chile earthquake, three types of geodetic observations were made during four time periods at nearby locations. These post-seismic observations were previously explained by post-seismic afterslip on the downdip extension of the 1960 rupture plane. In this study, we demonstrate that the post-seismic observations can be explained alternatively by volumetric viscoelastic relaxation of the asthenosphere mantle. In searching for the best-fitting viscosity model, we invert for two variables, the thickness of the elastic lithosphere, He, and the effective Maxwell decay time of the asthenosphere mantle, TM, assuming a 100-km-thick asthenosphere mantle. The best solutions to fit the observations in four sequential time periods, 19601964, 19601968, 19651973 and 19802010, each yield a similar He value of about 65km but significantly increasing TM values of 0.7, 6, 10 and 80 yr, respectively. We calculate the corresponding viscoelastic Coulomb stress increase since 1960 on the future rupture plane of the 2010 M8.8 Maule, Chile earthquake. The calculated viscoelastic stress increase on the 2010 rupture plane varies gradually from 13.1 bars at the southern end to 0.1 bars at the northern end. In contrast, the stress increase caused by an afterslip model has a similar spatial distribution but slightly smaller values of 0.13.2 bars on the 2010 rupture plane.

Journal

Geophysical Journal International – Oxford University Press

Published: May 1, 2014

Keywords: Seismic cycle Transient deformation Seismicity and tectonics Subduction zone processes Dynamics: seismotectonics South America

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