摘要
使用NEIC全球地震目录对比研究了印尼苏门答腊两次巨大地震的构造背景、震源参数和余震活动的时空特征,主要结果如下:①两次巨大地震发生在巽他海沟东侧长约1 000 km的8级地震空段上;②9.0级地震为单侧破裂,余震区规模巨大,长约1 300 km,宽260 km;8.7级地震为双侧破裂,余震区规模较小,长约700 km,宽150 km;③9.0级地震后数小时余震区迅速形成,其后不再扩展;而8.7级地震后4天形成400 km长的余震区,之后向南扩展,余震区内存在约150 km长的空段;④9.0级地震后近2个月,在余震区以南约400 km处发生5.8级显著地震,它位于8.7级地震的余震区内;⑤9.0和8.7级地震序列的b值分别为1.21和0.91,P值为0.72和0.86,h值为0.6和0.9。
Using the worldwide earthquake catalogue from NEIC, the tectonic background, source parameters and the time-spatial distribution of the two Sumatra earthquake sequences were studied. The results are as follows： ① The two huge earthquakes occurred in the east of the Sunda Trench where there is a 1000 km long seismic gap for M≥8.0 earthquake.② The fault plane of the M9.0 earthquake is unilateral rupture. Its aftershock area is tremendous with about 1 300 km long and 260 km wide. While the fault plane of the M8.7 earthquake is bilateral rupture. The aftershock area is smaller which about 700 km in length and 150 km in width. ③ The aftershock area was formed in several hours after the M9.0 earthquake, and then it did not expand. While a 400 km long aftershock area was formed in 4 days after the M8.7 earthquake occurred, then it extended towards the South direction. It is notable that there is a seismic gap in it. ④ A MS. 8 earthquake occurred in the South 400 km away from the aftershock area of the M9.0 earthquake, and it occurred in the aftershock area of M8.7 earthquake. ⑤ The b value of the two huge earthquakes is 1.21 and 0.91. P value is 0.72 and 0.86. and h value is 0.6 and 0.9 respectively.
出处
《国际地震动态》
2005年第10期1-8,共8页
Recent Developments in World Seismology
基金
中国地震局地震联合基金(青年基金)项目(605033)
关键词
巨大地震
地震序列
余震区
余震活动
huge earthquake
earthquake sequence
aftershock area
seismic activity of aftershocks
