Applicability of surface wave magnitude scale, Ms, and body wave magnitude scale, mb, in the study of seismicity of Northeast India and its adjoining region

Abstract

Richter gave an empirical relation between surface wave (Rayleigh Waves) magnitude , Ms, and body wave magnitude, mb, ( generally short P type body waves of period 1 sec). At the outset, we have tried to modify the Richter's relation by taking into account of the earthquake data of the North-East India and its adjoining region. Then we analyse the applicability of surface wave magnitude scale and body wave magnitude scale for the seismicity study of the region. Lastly the completeness of the earthquake datafile is checked. Various statistical methods are adopted in this present study. It has been seen that there is not much difference between the values of surface wave magnitude obtained from Richter's relation and modified Richter's relation. Since error is less,it would be better if modified Richter's relation is applied. From the study of applicability it is found that error is less if body wave magnitude is taken in the seismicity study. From the completeness analysis of the datafile it has been found that the datafile is complete from different period onwards for different magnitudes.