Tectonic geomorphology and Quaternary tectonic activity in the northwest Yunnan rift zone

In this paper, 3D visual image was constructed to interpret the distribution and geometric structure characteristics of active faults based on LANDSAT ETM+/ASTGTM data obtained in northwest Yunnan Province, and then some basin parameters which indicated the fault activities were extracted from 31 basins. Finally, the characteristics of active faults were summed up, and their activities were divided into three grades, i.e., strong, medium and weak. The results show that there exist significant difference and zoning in the faults’ activities within this zone. The activity of the Lijiang-Dali and Chenghai-Binchuan faults are strong, that of the Jianchuan-Qiaohou faults is of the medium grade, and that of the Tonggian-Weishan faults belongs to the weak grade. Strong active faults are distributed around the boundary of northwest Yunnan rift zone. In terms of the latitude, the activities of the faults in the south and the north are the strongest, whereas those in the central part are weak. In the light of the longitude, the faults’ activities on both east side and west side are strong, whereas those in the central part are weak. The differences of the fault activities are on the whole consistent with historical earthquake activities.