Lithospheric Density Structure of Andaman Subduction Zone from Joint Modelling of Gravity and Geoid data

Abstract

The Andaman subduction zone is the result of the oblique convergence of Indian plate that dives beneath Eurasian (Sunda) plate and one of the most seismically active regions. Structure and dynamics of the subduction zone are still a matter of investigations, inspite of a several studies were carried out earlier. In the present study, we have delineated the 2D density structure of the Andaman subduction zone through the joint modelling of gravity and geoid data set derived from the satellite altimetry and interpreted it in term of dynamics of the region. The major features of the density structures are: subduction of Indian plate up to ~ 180 km depth; anomalously thicker oceanic crust below the Ninetyeast Ridge, Sewell rise and in the shelf region; comparatively thin lithosphere under the overriding plate. Further, the lowest gravity anomaly marks the interaction of subducting oceanic crust with overriding upper mantle. © 2018, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.