GPS-derived heterogeneous inter- and intra-Indian plate deformation and its consequences

Abstract

We have analyzed 18 permanent GPS stations in and around the Indian plate to understand inter- and intraplate deformation patterns of infinitesimal strain variations. Differential deformation pattern along and across strike of the Himalaya shows westward decrease in crustal shortening with strong influence of the local geology. Subduction rate toward the eastern Indian plate boundary decreases drastically from south to north, indicating the development of locking condition. Excluding the western boundary of the Indian plate, which is under strong deformation due to flexuring of crust, the rest part of the Indian plate is rigid. Indo-Gangetic plain plays a key role in mountain building processes. The proposed kinematic model suggests the dominance of tensional forces and compressional forces toward craton margin and mountain front, respectively, with conditions for the development of proto-thrust in the form of step-out structures, south of MFT. Strain analysis shows western and eastern ends of the Himalayan front are under strong extensional and compressional strain, indicating the probability of future earthquakes. Similar high strain conditions also prevail on the west coast of the Indian craton as well Ganga–Brahmaputra Delta and Burma Arc region toward the northeastern corner of the Indian craton.