兰州地区活动构造格架与变形特征  

Active Tectonic Framework and Deformation Features in Lanzhou Area

作　　者：袁道阳[1] 刘小凤[1] 郑文俊[1] 刘小龙[1] 刘百篪[1] 

机构地区：[1]中国地震局分析预报中心兰州基地,730000

出　　处：《地质学报》2004年第5期626-632,共7页Acta Geologica Sinica

基　　金：国家重点基础研究发展规划项目 (编号 G19980 40 70 1-0 4);甘肃省"九五"攻关项目 (编号 GK973 -2 -110 A)的资助成果

摘　　要：兰州地区发育了北西西向和北北西向两组主导性活动构造带。大致以河口为界 ,东部地区主要为北西西向的马衔山—兴隆山左旋逆走滑活动断裂系 ,其新活动明显 ,是区内的主要控震断裂 ,112 5年兰州 7级地震就发生在其中的马衔山北缘断裂带的西端。河口以西为拉脊山北缘断裂和庄浪河断裂等一组北北西向的弧形逆冲断褶带 ,变形方式以逆断裂和断裂扩展褶皱为主 ,其新活动可能导致了 138年金城—陇西 6 34级地震、14 4 0年永登 6 14 级地震、苦水 5 12 级地震和 1995年永登 5 .8级地震的发生。兰州市区所在的兰州盆地则位于上述两组活动构造的交汇部位 ,其内同样发育了北西西向和北北西向两组具有成生联系的次级断裂 ,如刘家堡断裂、金城关断裂、雷坛河断裂及深沟桥断裂等 ,这些断裂具有孕育和发生中强震的构造条件。Lanzhou area developed two groups of dominant active tectonics: one group is NWW direction, another one is NNW direction. By the boundary of Hekou, the structure pattern of eastern area is simple and mainly by NWW direction Maxianshan—Xinglongshan reverse left lateral strike-slip fault system. Their new activity is very strong, so they formed the main controlled earthquake faults, the Lanzhou earthquake with magnitude 7 in 1125 had just happened in the west segment of this fault zone. In the western area of Hekou, there are a group of arc thrust—fold zones by NNW direction, such as the northern margin fault of Lajishan Mountain and Zhuanglanghe fault etc. The deformation is characteristic by fault propagation folding, their new activities had caused a series of earthquakes happening, such as Jingcheng—Longxi 634 earthquake in 138, Yongdeng 614 earthquake and Kushui 512 earthquake in 1440, Yongdeng Ms 5.8 earthquake in 1995 etc. Lanzhou basin is blended in the two group of active tectonics, there are also developed two groups of NWW and NNW direction secondary faults which relative each other, such as the Liujabu fault, Jingchengguan fault, Leitanhe fault and Shenggouqiao fault et al. these faults have the structural condition to breed and happen middle and strong earthquakes.

关 键 词：活动构造 新活动 8级地震 中强震 走滑 变形特征 构造带 断裂 弧形 市区 

分 类 号：P542[天文地球—构造地质学]