Probabilistic Assessment of Earthquake Hazards in the North-East Indian Peninsula and Hindukush Regions

The Himalayan region is one of the most seismic prone areas of the world. The North-East (NE) Indian peninsula and the Hindukush regions mark the zone of collision of the Indian and Eurasian plates. The probability of the occurrence of great earthquakes with magnitude greater than 7.0 during a specified interval of time has been estimated on the basis of four probabilistic models, namely, Weibull, Gamma, Lognormal and Exponential for the NE Indian peninsula and Hindukush regions. The model parameters have been estimated by the method of Maximum Likelihood Estimates (MLE) and the Method of Moments (MOM). The cumulative probability is estimated for a period of 40 years from 1964 and is ranging between 0.881 to 0.995 by the year 1995, using all four models for the NE Indian peninsula. The conditional probability is also estimated and it is concluded that the NE Indian peninsula would expect a great earthquake at any time in the remaining years of the present century. For the Hindukush region, the cumulative probability has already crossed its highest value, but no earthquake of magnitude greater than 7.0 has occurred after 1974 in this area. It may attribute to the occurrence of frequent shocks of moderate size, as seventeen earthquakes of magnitude greater than 6.0, including four greater than 6.4, have been reported until 1994 from this region.