延怀盆地活动断裂运动与现代构造应力场  

ACTIVE FAULT MOVEMENT AND RECENT TECTONIC STRESS FIELD IN YANHUAI BASIN

作　　者：谢富仁[1] 张红艳[1] 崔效锋[1] 荆振杰[1] 李瑞莎[1] 

机构地区：[1]中国地震局地壳应力研究所,北京100085

出　　处：《地震地质》2007年第4期693-705,共13页Seismology and Geology

基　　金：国家发展和改革委员会发改投资"城市活断层试验探测"项目(20041138);国家重点基础研究发展规划项目(2006CB202203)共同资助

摘　　要：延怀盆地包括延矾、怀涿两个相互连通的次级盆地。野外地震地质调查和断裂滑动观测表明:延矾盆地NE向活动断裂以右旋走滑为主,兼具正断层分量;怀涿盆地NE向活动断裂以正断为主,兼具右旋走滑分量;盆地内NW向断裂以左旋走滑为主,兼具正断层分量。采用野外观测取得的10个测点337条活断层擦痕数据,利用由断层滑动资料反演构造应力张量的方法,计算获得了研究区现代构造应力场的主要特征:延矾盆地现代构造应力场以NEE—近EW向挤压、NNW向—近SN向拉张为主要特征,应力结构均为走滑型。其最大主压应力(σ1)方向为N74°～88°E,平均倾角18°;最小主压应力(σ3)方向为近SN,近水平;中间主应力(σ2)倾角较陡,近垂直。怀涿盆地以NNW向拉张为主要特征,应力结构为正断型为主。其最大主压应力(σ1)平均倾角68°,近垂直;中间主应力(σ2)倾角较缓,最大的不超过35°;最小主压应力(σ3)方向为NNW—近SN向,近水平。断层滑动反演的结果与北京及周边地区由震源机制解资料反演分析结果基本一致。Yanhuai Basin contains Yanfan Basin and Huaizhuo Basin,which are connected one another. According to field seismo-geological investigation and fault slip observation, the active faults in northeast direction in Yanfan Basin are mainly dextral strike-slip,with some cases of normal fault. But in Huaizhuo Basin,the situation is opposite,the active faults in northeast direction are mainly normal faults,with some cases of strike slip. However,in the whole Yanhuai Basin, the active faults in northwest direction are mostly sinistral strike-slip,also with some cases of normal fault. By field investigation and observation,we got 337 data of active fault slickensides. And using the method of inversion of fault slip data, we can obtain the following characteristics of recent tectonic stress field in the research region. It is characterized by near NEE--EW maximum compressional stress and by near NNW--NS minimum extensional stress in Yanfan Basin,and the stress regimes are all of strike slip. The direction of the maximum principal compressional stress（ σ1 ） is N74°E - N88°E, and the average dip angle is 18°. The minimum principal compressional stress（ σ3 ）is nearly in NS direction, it＇s nearly horizontal. And the dip angle of middle principal compressional stress （σ2 ） is nearly vertical. However, in Huaizhuo Basin,it is characterized by NNW minimum extensional stress,and the stress regimes are mainly normal fault. Its maximum principal compressional stress（σ1 ）is nearly vertical, and the average dip angle is 68°. The dip angles of the middle principal compressional stress（ σ2 ）are flat,the largest is not over 35° and the minimum principal compressional stress（ σ3 ）is in NNW--NS direction ,it＇s nearly horizontal. The result inverted from fault slip data is in accordance with that inverted from focal mechanism solutions data in Beijing and its adjacent region.

关 键 词：延怀盆地 构造应力 断层滑动 最大主应力方向 

分 类 号：P315.1[天文地球—地震学]