Time Series Analysis of Landslide Evolution after Chi-Chi Earthquake

• Main Authors: Ting-Kuo Chiang, 江定國
• Other Authors: 林美聆
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/66246867558519511069

碩士 === 國立臺灣大學 === 土木工程學研究所 === 101 === Taiwan is located in the junction of tectonic plates, which causes complex and fragile geological conditions. The hazardous landslides were often induced by heavy rainfall and great earthquake. After Chi-Chi earthquake, landslides in Taiwan have been repeatedly reactivated more severely by typhoons due to the prolonged effect of earthquake. The threshold rainfall inducing landslides should increase gradually as the slopes become more stable with time proceeds. Therefore, study of the time series evolution of landslides and the variation of threshold rainfall could evaluate the influence of Chi-Chi earthquake on landslide disasters. In this research, time series remote-sensing images and DTM data were collected and corrected, for the interpretation of landslides by artificially and the establishment of selected landslide casual factors database. In analysis of landslides evolution, the landslides were distinguished into earthquake-reactivated type and non-earthquake -reactivated type for further discussion. Then rainfall analysis focusing on disaster events was performed to evaluate the threshold rainfall variation, for the validation of landslide evolution analysis. Finally, case study was included, in order to assist the discussion of the landslide evolution. In the May River basin, our inference is that the prolonged effect of Chi-Chi earthquake on landslides sustained about 5~7 years according to the landslide evolution analysis. Also, we found that the slopes become stable about 8~9 years after Chi-Chi earthquake by the rainfall variation analysis, which is consistent with the results above. But the results of case study did not fully correspond with the analysis of overall landslides evolution, which may due to landslides occurrence has unique environmental condition.