指導老師 : 董家鈞 老師 學生 : 李玟璇 報告日期 :2011/01/06

1. Landslide hazards triggered by the 2008 Wenchuanearthquake, Sichuan, ChinaYueping Yin . Fawu Wang . Ping Sun Landslides (2009) 6:139–151 指導老師:董家鈞 老師 學生:李玟璇 報告日期:2011/01/06

2. Introduction • Wenchuan earthquake-2008.5.12. • the distribution of the landslides; analyze the properties of landslides and landslide lakes 地工技術，第116期P.102

3. Distribution of landslides triggered by the earthquake • Geohazards have frequently occurred in the zone along the Longmenshan active fault system.

4. Table 1 Potential geohazards in the counties that experienced extremely severe effects caused by earthquake

5. Fig. 1 Comparative histograms of geohazards in the counties affected by theWenchuan earthquake before and after the earthquake 1169個 2782個 123% ↑ Total 237% ↑ 617% ↑ 480% ↑ 152% ↑

6. Fig. 2 Map of earthquake-triggered landslides in Beichuan 1 斷層帶 3 2

7. Beichuan 1 2 3 http://www.iseis.cuhk.edu.hk/gb/special/sichuan_rs.htm

8. Fig. 4 Cross section of the XinbeiMiddle School landslide in Beichuan length 560m width 200m average thickness 20m

9. Fig. 6 Cross section of the Tangjiashan landslide landslide-length 610m，width 800m landslide dam height 80-120m

10. Distribution of landslides triggered by the earthquake • Besides these large volume landslides and rockfalls, manysmall-scale landslides and rockfalls occurred along the road andcaused severe damage.(ex. national highway from Chengdu City to Jiuzhaigou Resort) http://www.iseis.cuhk.edu.hk/gb/special/sichuan_rs.htm

11. Fig. 5 Distribution of landslide-dammedlakes

12. Landslide-dammed lakes and their risk assessment • three factors: (1)Landslide dam height. (2)The capacity of the landslide-dammed lake. (3)The structure of the dam material.

13. Fig. 7 Three types of sliding surfaces of landslides triggered by the earthquake

14. Fig. 8 Stages of formation of stair, or terrace-shaped landslide

15. Example-the Chengxi landslide in Beichuan County Town Fig. 11 Cross section of the Chengxi landslide in Beichuan

16. Example-the Chengxi landslide in Beichuan County Town Oblique aerial view (a) and vertical air photo (b) of the Chengxi landslide in Beichuan

17. Example-the Donghekou landslide-debris flow in Qingchuan County Oblique aerial view of theDonghekoulandslide in QingchuanCounty

18. Example-the Donghekou landslide-debris flow in Qingchuan County Fig. 14 Cross section of the Donghekou landslide/debris flow, Qingchuan County

19. Conclusions • There are more than 10,000 potential geohazard sites induced by the Wenchuan earthquake, mainly by rockfalls, which reflect the effects of the earthquake on high, steep slopes in mountain areas, including topographic amplification effects on mountain summits and ridges.

20. Conclusions • The landslides can be classified into the following three types, i.e., convex, concave, and terraced, according to the shape of their sliding surface.

21. Thanks for your attention！