昆明市区浅部速度结构与隐伏断裂特征  

Shallow crustal velocity structure and hidden faults of Kunming city region

作　　者：于更新[1] 楼海[2] 王椿镛[2] 符力耘[1] 张建国[3] 秦嘉政[3] 杨润海[3] 李海鸥[4] 

机构地区：[1]中国科学院地质与地球物理研究所,中国北京100029 [2]中国地震局地球物理研究所,中国北京100081 [3]云南省地震局,中国昆明650224 [4]中国地震局地质研究所,中国北京100029

出　　处：《地震学报》2008年第5期500-507,550,共8页Acta Seismologica Sinica

基　　金：中国地震局地质研究所基本科研业务专项(DF-IGCEA-0608-2-8);国家重点基础研究发展计划项目(2004CB418401)共同资助

摘　　要：利用昆明市区的人工地震资料的Pg震相,通过三维有限差分方法对昆明地区浅部速度分布及构造进行反演,探讨了速度结构与隐伏断裂的关系以及主要活动断裂向深部的伸展情况.其中,普渡河—西山断裂在各种深度速度分布图上都在低速异常区的西边界上,是昆明盆地西侧的边界断裂,表现为以陡倾角向东倾斜,且向深部延伸深度较大.而普吉—韩家村断裂和黑龙潭—官渡断裂则控制盆地中部的低速异常区,向深部延伸深度相对较小,未穿过盆地基底界面.Kunming city region has a complex geological structure. In order to image the 3-D velocity structure of its shallow crust, finite-difference seismic tomography is used to invert the seismic data selected carefully from six-shot data. The result lays a foundation for discussion on the relationship between the obtained velocity structure and the hidden faults, and for illumination of the deep extension of main active faults surrounding Kunming city. Puduhe-Xishan fault lies on western margin of the Kunming basin and is just situated on west edge of the anomalous low velocity zone found at all depth levels. This indicates that this fault is a borderline fault of the Kunming basin. It can be concluded that the fault dips eastwards with a steep angle and has large extension depth. Puji-Hanjiacun fault and Heilongtan-Guandu fault play a role in controlling the anomalous low velocity region in middle basin. The extension depths of the two faults are comparatively small, without traversing the basin floor.

关 键 词：有限差分 速度结构 隐伏断裂 普渡河—西山断裂 

分 类 号：P315.2[天文地球—地震学]