30-09-2017, 11:28 AM
On 30 September 1993, the Killari event in central India is a rare occurrence of an earthquake occurring within a Precambrian crater. A pertinent question on seismicity in these regions is whether there is a pre-existing fault and, if so, what is its reactivation interval? Our studies in the 1993 rupture zone suggest that the Killari earthquake occurred in a region of previous seismic activity. The oldest push plates and fault cracks, presumably formed during previous episodes, were exposed in a deep trench. The studies also indicated a fault line escarpment, aligned with the current break zone. The morphological features of the area suggest the massive removal of the top of the hanging wall on the southwest side of the break. The existence of a prominent structure striking the northwest that crosses the epicentral zone is revealed in Landsat digital data. These data, coupled with the spatial trend of historical earthquakes along the striking northwest structure, reinforce the argument that the Killari earthquake is related to the reactivation of a preexisting fault.