关键词: 鲜水河断裂带, 地貌特征, 边界单元模型, 成因机制

Abstract:

Ground surface deformations due to some kinds of active structures have been modeled by the boundary element method. In terms of the theoretical results and the related geological data for the Xianshuihe fault zone, the formation mechanisms of the Dandu upheaval along the northwestern segment of the fault zone and the Huiyuansi pullapart basin in the middle have been discussed. It is concluded that the Dandu upheaval is caused by the local horizontal stress concentration due to the barrier of the fault bend to the left lateral strike slip on it; and the Huiyuansi basin reflects the effect of horizontal extension in the crust which is created by the non-equal left lateral strike slips on the two left stepping faults. Such structures may show the segmentation of the Xianshuihe fault zone and could control to some extent the start and end of some seismic ruptures.

Key words: Xianshuihe fault zone, Geomorphological feature, Boundary element model, Formation mechanism