The 1993 Killari (Latur), central India, earthquake: An example of fault reactivation in the Precambrian crust

Abstract

The September 30, 1993, Killari event in central India is a rare incidence of an earthquake occurring within a Precambrian craton. A pertinent question concerning seismicity in such regions is whether a preexisting fault exists and, if so, what is its reactivation interval?Ourstudiesinthe1993rupturezonesuggestthattheKillariearthquakeoccurred in a region of previous seismic activity. Older thrust sheets and fault gouge, presumably formedduringpreviousepisodes,wereexposedinadeeptrench.Thestudiesalsoindicated an obsequent fault-line scarp, aligned with the current rupture zone. The morphological features in the area suggest mass removal of the upper part of the hanging wall on the southwestern side of the rupture. Existence of a prominent northwest-striking structure passing through the epicentral zone is revealed in the digital Landsat data. These data, together with the spatial trend of historic earthquakes along the northwest-striking structure, reinforce the argument that the earthquake at Killari is related to the reactivation of a preexisting fault.