Evolution of large-scale landslide at Tuchang creek, Taiwan

The D077 study area is located on the right bank of Tuchang Creek in Wufeng Township, Hsinchu County, Taiwan. Two large-scale landslide events occurred in the D077 study area in 2004 and 2013, causing 14 casualties and disrupting traffic, seriously threatening downstream settlements. Until now, the rock slopes in the D077 study area are still in a state of toppling deformation and instability. In view of this, this study used multi-stage remote sensing, terrain analysis, geological survey, geophysical prospecting, drilling, and other data in the analysis of the evolution of large-scale landslides at D077 study area. The results show that the evolution of large-scale landslides (the D077 study area contains three sliding masses: S1, S2, and S3) can be divided into six periods: (1) the period of severe erosion of Tuchang creek and Chingchuan anticline, (2) rock mass decompression and toppling deformation period, (3) development of wedge failure trend of rock slopes at S1 sliding mass, (4) movement of S1 sliding mass and violent erosion of the S2 sliding mass slope toe, (5) toppling deformation develops rapidly at S2 sliding mass, (6) movement of S2 sliding mass and S3 sliding mass toppling deformation continues to develop. In the future, we predict that S2 and S3 will again cause debris sliding and large-scale rock mass sliding. This activity is also expected to threaten the safety of inhabitants and property in downstream of Tuchang creek.

Key words: large-scale landslide, toppling deformation, remote sensing, geological survey, geophysical prospecting, drilling