东江水库地震活动特征

AN ANALYSIS OF DONGJIANG RESERVOIR EARTHQUAKE AND ITS SEISMICITY CHARACTERISTICS

东江水库自1986年蓄水以来,在库区出现了频繁的地震活动,延续时间已达10年,最大地震为M_L 3.2级.分析认为,这些地震具有国内外一般水库地震的共同特征,属于水库诱发地震,其序列特征属震群型.由于水库坝高、容量大,且库区有活动断层和岩溶发育,诱震机制可能为荷载效应、断层孔隙水压效应和岩溶塌陷.

Since Dongjiang reservior being filled in 1986, the earthquake events occured frequently in this, area for as long as ten years, the largest of them is ML3.2. After analyzed the data, it is believed that these earthquakes have common characteristics as well as general resevior earthquakes at home and aboard. They belong to reservoir induced earthquakes. Their sequences of events are the type of swarms. As the dam is high and the reseroir's volume is very large , and there are active fault in the reservoir area and karst develops very well, the mechanism of earthquake inducement may be caused by load, pore water pressure and karst subsidence.