Constraints on the Source Parameters of the 26 January 2001 Bhuj, India, Earthquake from Satellite Images

The Bhuj earthquake of 26 January 2001 (Mw 7.6) was the largest intracontinental earthquake of the modern era of seismology. Field investigations did not provide any evidence of coseismic surface rupture or ground deformation due to primary faulting. We analyze pre- and postearthquake satellite images of the epicentral region to suggest that there was a significant change in the flooding pattern of the seasonal Rann of Kachchh lagoon after the 2001 and 2002 monsoons in the region of coseismic uplift. The maximum uplift is located about 15 km north of the reported epicenter and acted as a barrier against the northward draining rainwater runoff. Furthermore, the earthquake caused a northward shift in the southern limit of the Rann of Kachchh. We use this information to place constraints on the location and geometry of the earthquake rupture and suggest that the depth of the updip edge of the rupture is about 10 km.