Coseismic gravitational changes from great earthquakes

Jacob, Thomas; Gross, Richard; Wahr, John
thomas.jacob@colorado.edu

This study focuses on coseismic gravitational changes caused by the static deformation of the Earth generated from earthquakes. Using a normal mode summation scheme and source models for past great earthquakes, the initial, elastic, coseismic geoid height changes and surface gravity changes are evaluated. Emphasis is first made on the 1960 Chile earthquake and the 1964 Alaska earthquake. The coseismic geodetic signals from these earthquakes are compared to hydrological geodetic signals from the GLDAS/NOAH and CLM4.0 land surface models. Great earthquakes having occurred during the GRACE era are then investigated: the 2004 Sumatra earthquake and the recent 2010 Chile earthquake.