Kunming basin is a Cenozoic faulted basin under the control of mainly SN-trending active faults. In and around the basin, there are a total of eight major active faults. Seismo-geological survey and fault slip observa...Kunming basin is a Cenozoic faulted basin under the control of mainly SN-trending active faults. In and around the basin, there are a total of eight major active faults. Seismo-geological survey and fault slip observation show that the SN- and NE-trending active faults are mostly sinistral strike-slip faults, while the NW-trending faults are mostly dextral strike-slip faults. Using stress tensor inversion method with 706 active fault striation data at 22 measurement sites, we determined tectonic stress field of the study area. The result shows that modern tectonic stress field in and around Kunming basin is characterized by NNW-SSE compression, ENE-WSW extension, and strike-slip stress regimes. The maximum principal compressional stress （σ1） is oriented 335o;o, with an average dip angle of 21°; the minimum （σ3） is oriented 44o;3o, with an average dip angle of 14°, and the intermediate （σ2） has a high, or nearly vertical, dip angle. The inversion result from fault slip data is consistent with the result from focal mechanism solutions.展开更多
基金Special Fund for Scientific Research Institutions at Central Level (ZDJ2007-8)a Project sponsored by the Minis-try of Science and Technology of P. R. China (2006BAC13B01)
文摘Kunming basin is a Cenozoic faulted basin under the control of mainly SN-trending active faults. In and around the basin, there are a total of eight major active faults. Seismo-geological survey and fault slip observation show that the SN- and NE-trending active faults are mostly sinistral strike-slip faults, while the NW-trending faults are mostly dextral strike-slip faults. Using stress tensor inversion method with 706 active fault striation data at 22 measurement sites, we determined tectonic stress field of the study area. The result shows that modern tectonic stress field in and around Kunming basin is characterized by NNW-SSE compression, ENE-WSW extension, and strike-slip stress regimes. The maximum principal compressional stress （σ1） is oriented 335o;o, with an average dip angle of 21°; the minimum （σ3） is oriented 44o;3o, with an average dip angle of 14°, and the intermediate （σ2） has a high, or nearly vertical, dip angle. The inversion result from fault slip data is consistent with the result from focal mechanism solutions.
