SEISMICITY OF HIMALAYA VIS-À-VIS TECTONICS AND FOCAL MECHANISM
The active continent-continent collision between Indian and Eurasian plates have given rise to mighty Himalaya which separates the Tibetan plateau in the north from Indo-Gangetic plain in the south. This active collision since 65 million years has produced variety of geological features in the region in the form of large thrust faults running into several thousands of kilometers and many transverse features. The region has high earthquake productivity with four great earthquakes in a span of 53
... kes in a span of 53 years between 1897 and 1950 and many large earthquakes. It has been found by researchers that great and major earthquakes in the Himalaya occur on the northward dipping (with a dip of about 5-10) seismically active segment of detachment (Seeber et al., 1981;Ni and Barazangi, 1984;Molnar,1990). The small and moderate magnitude earthquakes are confined in a narrow belt, referred to as Himalayan Seismic Belt (HSB), which is around 50 km wide, which may be marked by 20-30 degree dip. In this study an earthquake catalog for the past 50 years is prepared; focal mechanism of all significant earthquakes is collected from various sources and a seismo-tectonic map of Himalaya is prepared with all major features which are digitized. The seismicity is studied with respect to geological features, focal mechanism.