Seismic activity following impounding of Mangla Reservoir

Abstract

This paper describes briefly the seismic network installed at Mangla in 1966 and recording continuously since then. Events of magnitude greater than one within a radius of 70 miles are presented and analysed. The record covers one year before impounding and six years of reservoir operation. The apparent increase in seismicity with impounding is shown to be due to an increase in sensitivity of the network. For the first six years of recording the frequency of events was roughly constant but it has dropped recently. Higher frequency of events tend to occur at higher reservoir level but with poor correlation. Rate and direction of change of reservoir level do not correlate with frequency.