RESERVOIR-INDUCED EARTHQUAKES

The best known site of reservoir-induced earthquakes in the world is located at Koyna, India where the largest known reservoir-induced earthquake of M 6.3 occurred on December 10, 1967 and activity still continues. There are a dozen other sites of possibly induced earthquakes in India. Indian scientists have contributed significantly in this field. Delineation of common characteristics of reservoir-induced earthquakes which in turn help to discriminate reservoir-induced earthquakes from normal earthquakes is one major contribution. Recent work has shown that possibly, reservoir-induced earthquakes of magnitude greater-than-or-equal-to 5 are preceded by a couple of magnitude greater-than-or-equal-to 4 earthquakes during the fortnight preceding the earthquake. At Koyna, and other reservoir sites of the world, rate of loading, highest levels reached and duration of retaining high levels are important factors in triggering reservoir-induced earthquakes.