2008年3月21日新疆于田7.4级地震序列特征及震前部分地震学异常特征
|
摘要
介绍了2008年3月21日新疆于田7.4级地震的基本参数、震区周围应力场背景及构造、地震序列特征等,分析了震前震区周围及相邻构造区域地震活动特征,对比分析于田序列和其后发生的汶川8.0级和乌恰6.9级地震的关系。结果显示,于田7.4级地震发生在阿尔金断裂与西昆仑断裂的交汇部位,可能是阿尔金断裂发生左旋扭错,牵引其西南端位于阿什库勒盆地的分支断裂发生张性破裂的结果。该地震序列为主-余型,最大余震为MS5.8,余震衰减较快,且具有一定的成丛性。震源机制解和震中分布可以看出,该地震具有单侧破裂特征。地震活动表明震前存在明显的中期和中短期异常,但未有短临异常出现。在汶川8.0级和乌恰6.9级地震前,该序列出现显著增强活动,具有一定的窗口效应。
The parameters,stress field background and tectonics,seismic sequence et al.are introduced in the paper,analyzing the seismic activity characteristics in the epicenter region and its adjacent region before the earthquake and analyzing the relation between Yutian seismic sequence,Wenchuan M8.0 seismic sequence and Wuqia M6.9 seismic sequence contrastively.The result showed Yutian M7.4 earthquake occurred in the region between Arjin fault and Western Kunlun fault,it maybe caused by left-lateral dislocation of Arjin fault,it is the tensile fracture result of the fault in the west northern region of Ashiku basin;the type of the seismic sequence is main shock-after shock,the strongest aftershock is MS5.8 earthquake,the aftershocks attenuated quickly,and occurred in group;the focal mechanism and the seismic activity showed there was medium and medium-short term abnormity before the earthquake,but there was not short-imminent abnormity;the seismic sequence activity became active before Wenchuan M8.0 earthquake and Wuqia M6.9 earthquake,which was window effect in some extent.
The parameters,stress field background and tectonics,seismic sequence et al.are introduced in the paper,analyzing the seismic activity characteristics in the epicenter region and its adjacent region before the earthquake and analyzing the relation between Yutian seismic sequence,Wenchuan M8.0 seismic sequence and Wuqia M6.9 seismic sequence contrastively.The result showed Yutian M7.4 earthquake occurred in the region between Arjin fault and Western Kunlun fault,it maybe caused by left-lateral dislocation of Arjin fault,it is the tensile fracture result of the fault in the west northern region of Ashiku basin;the type of the seismic sequence is main shock-after shock,the strongest aftershock is MS5.8 earthquake,the aftershocks attenuated quickly,and occurred in group;the focal mechanism and the seismic activity showed there was medium and medium-short term abnormity before the earthquake,but there was not short-imminent abnormity;the seismic sequence activity became active before Wenchuan M8.0 earthquake and Wuqia M6.9 earthquake,which was window effect in some extent.
引文
[1]王琼,聂晓红,温和平.2008年新疆于田MS7.3地震前区域地震活动和应力状态特征初步研究[J].地震学报,2009,31(3):235-244.
[2]尹光华,蒋靖祥,吴国栋.2008年3月21日于田7.3级地震的构造背景[J].干旱区地理,2008,31(4):343-349.
[3]聂晓红.新疆于田7.4级地震震源机制解结果[J].内陆地震,2008,22(2):114.
[4]陈学忠,蒋长胜,李燕娥.2008年3月21日新疆于田7.3级地震[J].国际地震动态,2008,352(4):18-28.
[5]许志琴,戚学祥,杨经绥,等.西昆仑康西瓦韧性走滑剪切带的两类剪切指向、形成时限及其构造意义[J].地质通报,2007,26(10):1 252-1 261.
[6]付碧宏,张松林,谢小平,等.阿尔金断裂系西段—西瓦断裂的晚第四纪构造地貌特征研究[J].第四纪研究,2006,26(2):228-235.
[7]王盛泽,高国英.新疆及其邻近地区现代构造应力场的区域特征[J].地震学报,1992,14(增刊):612-620.
[8]新疆地震局.天山地震目录及中强地震震源机制解[J].内陆地震,1997,11(增刊):127-147.
[9]马文涛,徐锡伟,曹忠权,等.震源机制解分类与川滇及邻近地区最新变形特征[J].地震地质,2008,30(4):926-934.
[10]李莹甄,聂晓红,夏爱国,等.2007年7月20日新疆特克斯5.9级地震及震前部分地震学前兆异常[J].中国地震,2008,24(4):370-378.
[2]尹光华,蒋靖祥,吴国栋.2008年3月21日于田7.3级地震的构造背景[J].干旱区地理,2008,31(4):343-349.
[3]聂晓红.新疆于田7.4级地震震源机制解结果[J].内陆地震,2008,22(2):114.
[4]陈学忠,蒋长胜,李燕娥.2008年3月21日新疆于田7.3级地震[J].国际地震动态,2008,352(4):18-28.
[5]许志琴,戚学祥,杨经绥,等.西昆仑康西瓦韧性走滑剪切带的两类剪切指向、形成时限及其构造意义[J].地质通报,2007,26(10):1 252-1 261.
[6]付碧宏,张松林,谢小平,等.阿尔金断裂系西段—西瓦断裂的晚第四纪构造地貌特征研究[J].第四纪研究,2006,26(2):228-235.
[7]王盛泽,高国英.新疆及其邻近地区现代构造应力场的区域特征[J].地震学报,1992,14(增刊):612-620.
[8]新疆地震局.天山地震目录及中强地震震源机制解[J].内陆地震,1997,11(增刊):127-147.
[9]马文涛,徐锡伟,曹忠权,等.震源机制解分类与川滇及邻近地区最新变形特征[J].地震地质,2008,30(4):926-934.
[10]李莹甄,聂晓红,夏爱国,等.2007年7月20日新疆特克斯5.9级地震及震前部分地震学前兆异常[J].中国地震,2008,24(4):370-378.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心