The Fault Slip Vector Inversion Kunming Regional Tectonic Stress Field

Through comprehensive analysis of previous researcher productions, we studied active faults in Kunming basin and its surrounding areas and focused on solving the problem of the study area fracture dynamics. We mainly studied the dynamic characteristics of active faults, that is where the tectonic stress fracture environment, driver fault movements cause of fault movement in the dynamic process of transformation, in order to promoting the region crustal dynamics in-depth environmental study.In the two field surey, on the eight main active fault in the research region,we determined tectonic stress tensor data at 33 measurement sites in the study area since Quaternary period, which is included in early Quaternary period of 11 measurement sites and late Quaternary period of 22 measurement sites using the methed of inversion from fault slip date.We have obtain following characteristics of two scheduled time tectonic stress field in the research region after Quaternary Period. the Quaternary Period initial stage,the tectonic stress field is mainly characteristic of nearly E-W compresion,S-N extension. The maximum principal compressional stress (σ1) is oriented average 260o, with an average dip angle of 28°; the minimum (σ3) is oriented average177o, with an average dip angle of 25°, and the intermediate (σ2) has a high, or nearly vertical, dip angle. the stress regime is o strike-sipe type.After the Later period stage, 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~350o, with an average dip angle of 21°; the minimum (σ3) is oriented 44o~93o, 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.By analysis main fault in research area, we Believe that there are also secondary—destructive earthquakes between the characteristic earthquakes jn the fault.According to the relation between slip rate,elapsed time and potential magnitudes ,we are calculated the main faults in the study area possess high potential.