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Regional gravity decrease after the 2010 Maule (Chile) earthquake indicates large‐scale mass redistribution

Regional gravity decrease after the 2010 Maule (Chile) earthquake indicates large‐scale mass... We report small but detectable changes in the GRACE satellites' relative trajectory after the M8.8 Maule, Chile earthquake on 27 February 2010 that can be used to delineate the shift in the gravity field. A gravity anomaly of −5 μGal with a spatial scale of 500 km was found east of the epicenter after the earthquake. Based on coseismic models, the long‐wavelength negative gravity change is primarily the result of crustal dilatation as well as surface subsidence in the onland region. The offshore positive gravity anomaly predicted from finite fault coseismic models is considerably smaller because the gravity changes due to surface uplift and interior deformation are opposite in polarity. Our study suggests a role for large‐scale gravity observations in deciphering changes of the Earth's interior during great earthquakes by filling in the seldom‐observed long‐wavelength spectrum of earthquake deformations as a complement to surface geodetic measurements and seismic data. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Geophysical Research Letters Wiley

Regional gravity decrease after the 2010 Maule (Chile) earthquake indicates large‐scale mass redistribution

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Publisher
Wiley
Copyright
Copyright © 2010 by the American Geophysical Union.
ISSN
0094-8276
eISSN
1944-8007
DOI
10.1029/2010GL045449
Publisher site
See Article on Publisher Site

Abstract

We report small but detectable changes in the GRACE satellites' relative trajectory after the M8.8 Maule, Chile earthquake on 27 February 2010 that can be used to delineate the shift in the gravity field. A gravity anomaly of −5 μGal with a spatial scale of 500 km was found east of the epicenter after the earthquake. Based on coseismic models, the long‐wavelength negative gravity change is primarily the result of crustal dilatation as well as surface subsidence in the onland region. The offshore positive gravity anomaly predicted from finite fault coseismic models is considerably smaller because the gravity changes due to surface uplift and interior deformation are opposite in polarity. Our study suggests a role for large‐scale gravity observations in deciphering changes of the Earth's interior during great earthquakes by filling in the seldom‐observed long‐wavelength spectrum of earthquake deformations as a complement to surface geodetic measurements and seismic data.

Journal

Geophysical Research LettersWiley

Published: Dec 1, 2010

References