Geodetic constraints on the Bhuj 2001 earthquake and surface deformation in the Kachchh Rift Basin

Abstract

GPS measurement of historic survey points in the region of the Mw 7.6 Bhuj earthquake of 26 January 2001 reveal a rupture area 25 km × 15 km, with the top of the rupture located at least 9 km beneath the surface. The geodetic data also reveal north-south convergence of ∼18 mm/yr across the Rann of Kachchh since 1856. Convergence and the occurrence of south-dipping reverse earthquakes on the northern edge of the Kachchh mainland suggest that the region is one of incipient or ongoing tectonic uplift. The small rupture of the Bhuj earthquake indicates that other earthquakes are likely to occur in the region, although few clues exist to indicate the progression of future ruptures.