【摘要】 昆明盆地是一个受南北向活动断裂控制的新生代断陷盆地.昆明盆地及其周边地区共有8条主要断裂带,野外地震地质调查和断裂滑动观测表明,南北向和北东向活动断裂以左旋走滑为主,北西向活动断裂以右旋走滑为主.采用野外观测取得的22个测点共706条活断层擦痕数据,利用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主要特征:昆明盆地及其周边地区现代构造应力场以北北西—南南东向挤压、北东东—南西西向拉张为特征,其最大主压应力(σ1)方向为333°—2°,平均倾角21°;最小主压应力(σ3)方向为44°—93°,平均倾角14°;中间主应力(σ2)倾角较陡,近垂直.应力结构均为走滑型.断层滑动反演结果与震源机制解资料分析结果基本一致.更多还原

【Abstract】 Kunming basin is a Cenozoic faulted basin controlled by South--North striking active faults. In and around the Kunming basin there are totally 8 major active fault zones. Result of field geologic survey and fault slip observation indicates that the N--S and NE--SW striking faults are mainly of left-lateral strike-slip motion,while NW--SE striking ones are mainly right-lateral faults. We have measured 706 slicken-slides on active faults at 22 observation sites. By inverting these fault slip data we obtained the following result on the characteristics of contemporary tectonic stress field in the research region: In the Kunming basin region the maximum compression is generally in horizontal NNW--SSE direction, while the principal relative tension appears nearly in horizontal NE--SW,and the stress regime is of strike-slip faulting type. The direction of the maximum compressional stress(σ1)is in 333°—2°, and the average pluge is 21°. The minimum principal stress(σ3) is in 44°—93° , and the average plunge is 14°, and the intermediate principal stress(σ2) is nearly vertical. The result obtained by inverting fault slip data is in accordance with that by inverting earthquake focal mechanism solutions in Kunming and its adjacent region.更多还原