Role of flexure in earthquake triggering along the Western Ghat escarpment, India

Abstract

The occurrence of earthquakes near reservoirs in the region of the Western Ghat escarpment far exceeds the reported rate in other areas of peninsular India. Reservoir loading and induced pore pressure are generally thought to be triggering earthquakes, but in order to explain the anomalous rates of occurrence in the Western Ghat, we invoke the additional effects of elastic plate flexure. The height of the escarpment is usually considered to be maintained by flexure in the east–west direction. Intense erosion and sediment loading further control its evolution. We propose that this promotes failure at shallow depth by a reduction of the normal stress on escarpment-parallel sub-vertical planes in the region. The same mechanism has been proposed to operate globally in several other escarpment regions along passive margins.