2003年9月27日中、俄、蒙边界M_S7.9地震震源机制及破裂过程研究  

MOMENT TENSOR INVERSION AND SOURCE RUPTURE PROCESS OF THE SEPTEMBER 27, 2003 M_S=7.9 EARTHQUAKE OCCURRED IN THE BORDER AREA OF CHINA, RUSSIA AND MONGOLIA

作　　者：赵翠萍[1] 陈章立[2] 郑斯华[2] 刘杰[2] 

机构地区：[1]中国地震局地球物理研究所 [2]中国地震局地震预测研究所,中国北京100036

出　　处：《地震学报》2005年第3期237-249,共13页Acta Seismologica Sinica

基　　金："十五"攻关项目(2004BA601B010401)资助

摘　　要：从IRIS全球数字地震台网长周期记录中,选取震中距位于30°～90°的垂直向远震P波资料,反演了2003年9月27日中、俄、蒙边界MS7.9地震及10月1日MS7.3强余震的地震矩张量解,研究了MS7.9地震的时空破裂过程.参考余震的空间分布及周围断层走向,确定MS7.9地震发震断层走向127°、倾角为79°、滑动角为171°.MS7.9地震震源破裂过程反演结果表明,整个破裂过程持续了37s,释放标量地震矩0.97×1020N·m.破裂主要发生在长110km,宽30km的中地壳以上,最大位错3.6m.起始破裂处不是滑动量最大的地方.断层面上显示出两个显著的、滑动量超过2.0m的破裂区.破裂传播至MS7.3震源区附近时,滑动量迅速减小,显示出破裂传播过程的受阻停止,反映了障碍体引起的破裂过程的不均匀性.We conducted the moment tensor inversion and studied source rupture process for M_S=7.9 earthquake occurred in the border area of China, Russia and Mongolia on September 27, 2003, by using digital teleseismic P-wave seismograms recorded by long-period seismograph stations of the global seismic network. Considering the aftershock distribution and the tectonic settings around the epicentral area, we propose that the M_S= 7.9 earthquake occurred on a fault plane with the strike of 127°, the dip of 79° and the rake of 171°. The rupture process inversion result of M_S=7.9 shows that the total rupture duration is about 37 s, the scalar moment tensor is M_0=0.97×10 20 N·m. Rupture mainly occurred on the shallow area of 110 km long and 30 km wide, the location in which the rupture initiated is not where the main rupture took place, and the area with slip greater than 0.5 m basically lies within 35 km deep middle-crust under the earth surface. The maximum static slip is 3.6 m. There are two distinct areas with slip larger than 2.0 m. We noticed that when the rupture propagated towards northwest and closed to the area around the M_S=7.3 epicenter, the slip decreased rapidly, which may indicate that the rupture process was stopped by barriers. The consistence of spatial distribution of slip on the fault plane with the distribution of aftershocks also support that the rupture is a heterogeneous process owing to the presence of barriers.

关 键 词：中、俄、蒙边界地震 矩张量反演 震源破裂过程 障碍体 

分 类 号：P315.33[天文地球—地震学]