TRIGGERING OF LOCAL EARTHQUAKES IN THE QAIDAM BASIN BY THE SUMATRA EARTHQUAKE

A magnitude 9.0 earthquake,which was the strongest earthquake in the past four decades,occurred just off the northwest coast of Sumatra,Indonesia,on December 26,2004.It caused serious damage and casualties.This large earthquake left as long as more than 1000 seconds of records at the Shizigou seismograph station in the western part of the Qaidam basin a distance of 4000 km from the epicenter.It has also triggered the local seismic activity in the western Qaidam basin.The frequency of the local earthquakes in the day after the occurrence of the large earthquake was 10 times as high as it had been.From the distribution of the local seismic activity triggered by the large earthquake,the causative faults triggering the local earthquakes in the western Qaidam basin are the Huatugou fault and Hongliuquan fault on the southern side of the Yingxiong Range.