摘要
对1992 年至1996 年4 月发生在40°00′～41°10′N,108°20′110°30′E 范围内的51 次ML≥2 .0 地震空间位置与包头6 .4 级主震及其余震空间位置的相互关系研究表明,前期地震的活动展布方向与包头6 .4 级主震震源机制解主压应力方向一致,震源深度为9 ～34 km ,78% 的地震活动在20 km 以浅的地层内,前期小震活动使包头—呼和浩特地区形成了空区.包头地震发生在此空区内.包头6 .4 级主震震源较深,余震的震源都比主震的浅.在包头6 .4 级地震发生的前1 ～2 a 时间内,围绕主震空间位置发生了一系列小震,这些小震活动可能对包头地震的成因有着较大影响作用.笔者认为包头6 .4 级地震是脆性破裂,属左旋走滑兼具正断错动.
By researching the spatial relationship of the Baotou M S6.4 mainshock,aftershocks and 51 M L≥2.0 foreshocks which occurred in the region of 40°00′～41°10′N,108°20′～110°30′ from 1992 to the April,1996,it is shown that the direction of foreshocks distribution is consistent with the principal stress orientation in focal mechanism solution of the Baotou M S6.4 mainshock,their focal depths are in the scope from 9 to 34 kilometers,78 percent of them occurred beyond the depth of 20 kilometers,the small earthquakes activities made the region from Baotou to Huhhot form a gap.The Baotou M S6.4 earthquake occurred just in the gap.It is considered that the earthquake was brittle fracture,normal and sinistral strike slip.
出处
《西北地震学报》
CSCD
1999年第4期411-416,共6页
Northwestern Seismological Journal
关键词
震源深度
小震活动
破裂方式
地震前兆
空间分布
Focal depth
Small earthquake activity
Rupture pattern
Baotou M S6.4 earthquake
