Characteristics of seismic activity before several large Sumatra, Indonesia, earthquakes

摘要

@@ Two great earthquakes of MS8.5 and MS8.3 determined by the China Earthquake Networks Center(CENC)occurred successively on September 12 and 13,2007 in the sea area to the South of Sumatra,Which is another group of large earthquakes after MS8.7 event on December 26,2004 and MS8.5 event on March 29,2005.The magnitudes of these earthquakes determined by the National Earthquake Information Center of USA(NEIC)are MW9.0(26 December 2004),MW8.7(29 March 2005),MW8.4(12 September 2007)and MW8.1(13 September 2007),respectively.