Evolution of b-values before large earthquakes of mb ≥6.0 in Andaman region

Abstract

We have considered six earthquakes of m_b ≥6.0, with focal depths within 45 km, in Andaman region during 2000 to 2012 to examine the spatial variations of b-value at epicentre within a one-year period prior to the occurrence of the earthquakes. We have found a correlation between the low b for the one year time interval and the occurrence of large events. The epicentral b-values of six earthquakes are lower than 1.0 and five out of six earthquakes show very low b-value at the epicentre. Our study may indicate that b-value can be employed as a possible precursor for the forecasting of a major earthquake.