TEMPORAL AND SPATIAL VARIATIONS OF b-VALUE AND ITS IMPLICATIONS

Abstract

Entire region of the Himalaya‟s arc is one of the most seismically active regions of the world. This is evident through the large number of earthquakes occurred in this belt.Earthquake data for the period from 1897-2015 largely compiled from Global ISC and USGS databases has been used in this study.Some earthquake data from the bulletins of India Meteorological Department are also used. Magnitude of completeness and Gutenberg-Richter (GR) recurrence parameters i.e. „a‟ and b-values have been determined for the de-clustered homogenized catalogue with respect to different depths and location using Maximum curvature(MAXC) and Entire magnitude method(EMR).Temporal analysis has also been done using Maximum curvature method.The results obtained form both methods have been analysed.The study region i.e. Himalaya region has been divided six blocks longitudinally in the intervals of five degree each.For the temporal analysis the data ranging from 1956 to 2015 has been divided into 3 sub-groups for b-vlaue computaton.Mc,„b‟ and „a‟ values have been estimated with respect of each zone,and the variations in the values of these parameters have been analyzed, upto 30km the computed value has been observed with the depth.For the Himalayan region b-value range from 0.5 to 1.5.