论文部分内容阅读
大同震区先后在 1989、1991和 1999年发生MS >5地震 ,利用大同遥测地震台网的记录资料进行比较精确的地震序列震源定位 ,结合宏观烈度分布和震源机制解资料 ,详细地分析对比了 3次子序列的异同。结果显示 ,1999年MS5 .6地震的震源断层是走向NWW、长 16km、宽12km、埋深 5km以下、倾角近直立的左旋走滑断层。而前 2个子序列是NNE为主的右旋走滑断层活动所致 ,表明地震破裂方向发生了变化。这种 2个以上方向先后出现、并且强弱有别的地震破裂是普遍存在的 ,表明震源环境的复杂程度与地震序列的类型有关。虽然震区存在NE向的大王村断裂和NW向的团堡断裂 ,但目前没有证据说明震源断层和 2条构造断层连通。 3次子序列的震源断层都是走滑断层 ,也和 2条构造正断层有别。 1999年的子序列可能属于新破裂。
The MS> 5 earthquakes occurred successively in 1989, 1991 and 1999 in Datong earthquake zone. Using the recorded data of Datong telemetric seismic network to conduct more accurate seismic sequence location, combined with the macroscopic intensity distribution and focal mechanism solution data, a detailed analysis and comparison were made The similarities and differences of 3 sub-sequences. The results show that the focal fault of the MS5. 6 earthquake in 1999 is a left-lateral strike-slip fault NWW, 16 km long, 12 km wide, and buried below 5 km. The first two sub-sequences are caused by NNE-dominated dextral strike-slip faults, indicating that the direction of earthquake rupture has changed. The emergence of more than two directions and the existence of strong and weak earthquake ruptures are ubiquitous, indicating that the complexity of the source environment is related to the type of earthquake sequence. Although there are NE-trending Dawangcun faults and NW-trending Baobab faults in the quake zone, there is no evidence that the hypocenter and the two tectonic faults are connected. The focal subfaults of the third sub-series are all strike-slip faults, which are also different from the two normal faults. The 1999 subsequence may belong to a new rupture.