Spatial variation of seismic b- values across the NW Himalaya

摘要

The frequency?￠????magnitude distribution is investigated along the entire north-western Himalaya (28???°?￠????36???°N; 72???°?￠????81???°E). The analysis includes a complete set of 1819 earthquakes of M b ?￠???￥ 2.9 taken from the International Seismological Catalogue (ISC) bulletin which occurred between 1964 and 2010. The study area has been divided into three blocks (A, B and C) that include the Kashmir, Kangra?￠????Chamba and Garhwal?￠????Kumaun segments, respectively. The b -value of each block has been determined to see the disparity among the different segments. A comprehensive study of the spatial mapping of frequency?￠????magnitude distribution is also made for the whole area. Significant variations in the b -value are detected with b ranging from b ?￠???? 0.6 to 1.3. The study shows that the accumulated stresses are high at the Kumaun as well as in the Kangra?￠????Chamba region which may indicate the possibility of future large earthquakes at these locations.