The Origin of Potential Large-Scale Landslide Areas in Taiwan – A Preliminary Study

• Main Authors: Lin, Chien-Yu, 林建宇
• Other Authors: Liao, Jyh-Jong
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/22r9ag

碩士 === 國立交通大學 === 土木工程系所 === 107 === The thesis aims to develope an inventory of the 2523 potential large-scale landslide areas, which were delineated by Forestry Bureau, COA, Executive Yuan in 2012-2015. The 2523 potential landslide areas distribute in the national forests belonging to the watersheds of the Dajia River, the Zhuoshui River, the Zengwun River, or the Gaoping River. The parameters of the inventory include geological factors and terrain factors. The inventory was adopted for statistical analysis to summarize the important geological and geomorphical factors of the landslide areas and to propose theorigin of the 24 medium to high risk potential landslide areas of the 2523 landslide areas. According to the result of statistical analysis, most of the area of the potential landslide are less than 30 hectares. The average elevation of the potential landslide areas is between 1000m and 2500m and the relief of elevation is concentrated at 200~600 meters. The average slope inclination is 30~40 degrees. Most of the main strata are the Miocene or Oligocene slates . The potential landslide areas are affected by the river erosion is more strong than the influence by geological structures. Most of the longitudinal profile of the pontenial landslide areas are flat orconvex and most of the cross-section are straight. Most of the potential landslide areas are eroded by gullies. According to mgeomorphic features, which areinterpreted by LiDAR terrain, the 24 medium to high risk potential landslide areas can be divided into four categories. Type 1 is the potential landslide areas which have the topographical features of gravitational slope deformation. Type 2 potential landslide areas are the relic of paleo landslides c induced by gravitational buckling failure or topplinig failure. Type 3 is the relic of paleo rock slope failures including rock fall and plane failure. The potential landslide areas with gully erosion belong to Type 4. The research result found that the development of most of the potential areas are controlled by river erosion; the order of rivers at is larger than 3. And by the classification result, most of all medium to high risk potential landslide areas had collapsed long time ago.