Strange attractor dimension as a new measure of seismotectonics around Koyna reservoir, India

Abstract

The fractal dimension of a strange attractor based on 44,792 earthquakes around Koyna reservoir in the period 1967–1981 has been determined for three periods during which the main shock of 1967 ( M 6.5) and the largest aftershocks of magnitude 5.0 in 1973 and 1980 occurred. It was found that the fractal dimension remains almost the same and that at least five parameters are needed for earthquakes to be predictable in the region. The non-integral dimension obtained and the positive value of the largest Lyapunov Exponent show that the system is chaotic. The phase space portrait of the Koyna earthquake also shows that the trajectories lie on a strange attractor. It is surmised that the fractal dimension is a new measure of seismotectonics around Koyna region.