Global seismic temporal pattern and enhanced seismicity since 2000
Temporal pattern of global seismicity indicates temporal clustering of large earthquakes (Mw≥8.2) followed by relative quiescence (stress shadow). It is a characteristic seismic pattern along the plate boundaries. Clustering of the largest earthquakes during 1950s to 1960s followed by the extended period of low-moment release until 2003 and then again heightened moment release since 2004 has been observed, which represents a seismic temporal pattern of 50 years period. Similarly, the Alpine-Himalaya-Andaman-Sumatra (AHAS) belt and stable Indian Peninsular region have showed repeated temporal pattern of high and low seismicity. In the AHAS belt, seismicity was high during 1897 to 1916, low during 1917 to 1933, high again during 1934 to 1951, low again during 1952-1999 and since 2000 onwards seismicity has again enhanced. It has been observed that when there were no great earthquakes in Himalaya, the Peninsular India experienced, during that period, more number of M≥6 earthquakes.