Study of Satellite Gravity over the Sumatran Earthquake Region

The devastating earthquake (and the corresponding tsunami) that struck the Indian Ocean near Sumatra (Indonesia) on 26 December, 2004 was extremely powerful. In the present study, a very high resolution 3D gravity image has been generated over a part of eastern Indian offshore over the Sumatran earthquake region. Four latitudinal gravity profiles have been generated across the epicenter/aftershocks regions and down below. A drastic change of gravity anomaly patterns (~130 mGal) near the epicenter and the aftershocks regions could be observed, which is however slowly diminishing as one goes away from the epicenter. It is expected that the large changes in gravitational values near the subduction zones may cause severe disturbances leading to the plate motions where as minor/major gravitational differences in other areas may be due to the changes in densities of different lithospheric zones/sedimentary layers beneath that area in a comparatively isostatically equilibrium region. ----------------------------------------------------------------------------------------------------------*Corresponding Author