关键词: 活动构造, 活动块体, 强震复发模型, 川西

Abstract: There exist several groups of seismogenic active faults at the conjoined areas of the Chuandian,Bayankala and Huanan active blocks along the eastern margin of the Qinghai-Tibetan Plateau. Owing to existence of transverse secondary active faults,the Chuandian Block can be further divided into the Middle Yunnan and Northwestern Sichuan sub-blocks,and the Longmenshan sub-block at the easternmost end of the Bayankala Block. Joint exploration of the crustal structure shows that low-velocity layers exist in the crust of the Chuandian and Bayankala Blocks. These low velocity layers correspond also to high conducting layers and they are the cause of frequent earthquake occurrence in the upper crust. Geologic study and GPS surveying indicate that the tectonic motion of the blocks in this region is accounted to be a complex or superimposition of three basic types of motions: southeastward sliding,rotating on vertical axis,and uplifting,but there is difference in the geologic slip rate and GPS rate. Besides,this paper collects the database of the geologic slip rates and GPS slip rates for the active faults in the region and major scientific problems are also discussed at last.

Key words: active tectonics, active blocks, recurrence behavior of strong earthquake, western Sichuan Province