GPS derived crustal deformation analysis of Kachchh, zone of 2001(M7.7) earthquake, Western India

Abstract

In this study, we present the first estimates of crustal deformation using the time series (2009–2015) from GPS Network of Gujarat (GNG), comprising 10 GPS continuous and 5 campaign mode stations in the seismically active Kachchh region. The GPS data were processed using GAMIT/GLOBK/GLORG software and results reveal very low amount of intra-plate deformation in this part of the Indian plate. International Terrestrial Reference Frame (ITRF) velocity of sites deduced in this study indicates 46–51 mm/yr of motion with one sigma uncertainty. A maximum of ≈3.0 ± 0.5 mm/yr of deformation has been estimated in the Kachchh region. However, estimated strain rate from the velocity field indicates a maximum strain of 5 nano-strain/yr. Our results indicate deformation of a weak zone, where earthquakes may trigger due to the combination of local as well as regional stress. The analysis of strain tensors near the major fault systems (KMF, KHF, SWF and GF) indicates strike normal compression in the area. The low rate of deformation, derived in the present study, is important to understand the seismic hazard level in this part of the Indian intra-Plate.