台东太麻里集水区崩塌因子探讨

Exploration on the Landslide Factors in Taitung Taimali River Watershed

台湾位于板块交界处，东部地质较为破碎且地震频繁，加上地理位置关系，台风经常侵袭台湾且携带极大雨量，易使山区发生山崩、地滑、土石流等灾害，严重威胁坡地居民生命及财产安全。2009年8月莫拉克台风挟带高强度降雨，在东部地区造成严重崩塌灾害，太麻里流域总崩塌面积高达2501hm2。本研究应用相关分析和主成分分析，探讨地文因子及水文因子与崩塌地的关系，研究结果显示：地文因子方面，有77．2％崩塌皆小于1hm2，且崩塌高程多落于500～1500m之间；水文因子方面，因地理位置的关系，太麻里集水区流域上游与下游雨量观测值相差约1000mm，显示太麻里集水区上游雨量充沛，致使该地区崩塌地多位于中、上游；综合各因子对崩塌地的影响，认为致使本研究区崩塌地发生的因子为坡度与高程，其次为降雨因素。

Located at the plate boundary, Taiwan Province has frequent earthquakes with the broken geology at east- ern part of the Province. In addition, lied in the passing route of typhoon, Taiwan Province is easily affected by the natural disasters in the mountainous areas such as landslide, debris flow and mud flow due to the heavy raining storms that seriously threaten the local residents＇ lives and property security. In August 2009, Typhoon Morakot struck Taiwan Province, carrying the high intensity and long - duration rainstorm that caused the severe landslide disaster in Taitung. The total landslide areas of Taimali watershed reached up to 2,501hm2. By using the correlation analysis and the prin- cipal component analysis methods, it was studied the relationships between the geographic and hydro -logical factors and the landslide land. The results show that, from the aspect of geographic factors, 77.2% of landslide areas are less than lhm2, with the landslide elevation between 500 to 1,500m. While from the aspect of hydro - logical factors, be- cause of the different geographical locations, the difference of rainfall observation value at the upstream and down- stream of Taimali watershed is about 1,000 mm. It appeared that rainfall at the upstream of Taimali watershed is abun- dant, so that most of the landslide areas are located at the up and middle stream. In brief, it is concluded that the oc- currence factors of the landslide in this area are slope and elevation, and then the rainfall factor.