1999年山西大同M_S5.6地震的震源断层
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摘要
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 earthquakes with M S>5.0 occurred in Datong seismic area in 1989,1991 and 1999.The precise hypocenter measurement of earthquake sequence is taken by the data of the remote sensing seismic station network in Datong. Using those results together with macro intensity distribution and focal mechanism, we analyze the difference among three subsequences. The result shows that the focal fault of M S5.6 earthquake of 1999 is left-lateral strike slip fault, which is strike NWW,16km in length, 12km in width, 5km in depth and nearly straight angle in dip. The two previous earthquake sequences cause from right-lateral strike slip faults of strike NNE. This shows the rupture direction of 1999 earthquakes changes.It is general that rupture has more than two directions, appears successively and has different strengths. This shows that the complex degree of hypocenter circumstance is related to the type of earthquake sequences. There are NE Dawangcun fault and NW Tuanbu fault in seismic area, but no proof indicates the connection between focal faults and two tectonic faults. The feature that focal faults of three subsequences are strike slip is different from the two tectonic faults.1999 subsequence possibly belongs to new rupture.
The earthquakes with M S>5.0 occurred in Datong seismic area in 1989,1991 and 1999.The precise hypocenter measurement of earthquake sequence is taken by the data of the remote sensing seismic station network in Datong. Using those results together with macro intensity distribution and focal mechanism, we analyze the difference among three subsequences. The result shows that the focal fault of M S5.6 earthquake of 1999 is left-lateral strike slip fault, which is strike NWW,16km in length, 12km in width, 5km in depth and nearly straight angle in dip. The two previous earthquake sequences cause from right-lateral strike slip faults of strike NNE. This shows the rupture direction of 1999 earthquakes changes.It is general that rupture has more than two directions, appears successively and has different strengths. This shows that the complex degree of hypocenter circumstance is related to the type of earthquake sequences. There are NE Dawangcun fault and NW Tuanbu fault in seismic area, but no proof indicates the connection between focal faults and two tectonic faults. The feature that focal faults of three subsequences are strike slip is different from the two tectonic faults.1999 subsequence possibly belongs to new rupture.
引文
刁桂苓、于利民、李钦祖,1995,大同2次MS5.8地震序列的震源区应力场对比分析,地震,4,345～352。
刁桂苓、于利民、孙佩卿等,1993,1989年大同震群的体破裂特征,地球物理学报,36(3),360～368。
丁学文、丁有礼、郭星全等,2000,1999年大同-阳高5.6级地震宏观烈度考察报告,山西地震,(1),2～6。
高阿甲,2000,华北地震震源机制分析,地震地磁观测与研究,21(1a),53～59
郭星全、王跃杰,2000,1999年山西大同-阳高5.6级地震灾害损失评估,山西地震,(1),7～15。
马瑾、马胜利、刘力强等,2000,交叉断层的交替活动与块体运动的实验研究,地震地质,22(1)65～73。
苏宗正、程新原,1992,1989年大同-阳高地震的地质环境与地震构造,山西地震,(1),19～30。
王国强、安卫平、兰青龙等,1992,1991年大同-阳高5.8级地震宏观烈度与地震构造,山西地震,(1),41～47。
王鸣、王培德,1992,1989年10月18日大同-阳高地震的震源机制和发震构造,地震学报,14(4),407～415。
朱艾斓、刁桂苓、张四昌,1999,1989年和1991年大同-阳高2次地震震源断层的三维特征,山西地震,(3),15～20。
张四昌、刁桂苓、于利民,1993,1989年大同-阳高地震序列的破裂特征,地震学报,15(增刊),524～528。
张四昌,1991,中国大陆共轭地震构造研究,中国地震,7(2),69～76。
刁桂苓、于利民、孙佩卿等,1993,1989年大同震群的体破裂特征,地球物理学报,36(3),360～368。
丁学文、丁有礼、郭星全等,2000,1999年大同-阳高5.6级地震宏观烈度考察报告,山西地震,(1),2～6。
高阿甲,2000,华北地震震源机制分析,地震地磁观测与研究,21(1a),53～59
郭星全、王跃杰,2000,1999年山西大同-阳高5.6级地震灾害损失评估,山西地震,(1),7～15。
马瑾、马胜利、刘力强等,2000,交叉断层的交替活动与块体运动的实验研究,地震地质,22(1)65～73。
苏宗正、程新原,1992,1989年大同-阳高地震的地质环境与地震构造,山西地震,(1),19～30。
王国强、安卫平、兰青龙等,1992,1991年大同-阳高5.8级地震宏观烈度与地震构造,山西地震,(1),41～47。
王鸣、王培德,1992,1989年10月18日大同-阳高地震的震源机制和发震构造,地震学报,14(4),407～415。
朱艾斓、刁桂苓、张四昌,1999,1989年和1991年大同-阳高2次地震震源断层的三维特征,山西地震,(3),15～20。
张四昌、刁桂苓、于利民,1993,1989年大同-阳高地震序列的破裂特征,地震学报,15(增刊),524～528。
张四昌,1991,中国大陆共轭地震构造研究,中国地震,7(2),69～76。
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