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Regional gravity decrease after the 2010 Maule (Chile) earthquake indicates large‐scale mass redistribution
Author(s) -
Han ShinChan,
Sauber Jeanne,
Luthcke Scott
Publication year - 2010
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 - 10.1029/2010gl045449
Subject(s) - geology , seismology , geodetic datum , epicenter , gravity anomaly , geodesy , free air gravity anomaly , subsidence , bouguer anomaly , interferometric synthetic aperture radar , anomaly (physics) , geophysics , geomorphology , synthetic aperture radar , structural basin , paleontology , physics , remote sensing , condensed matter physics , oil field
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 μ Gal 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.