南投縣仁愛鄉崩塌特性分析及崩塌風險模式建構

Abstract

The study developed landslide susceptibility and risk models based on landslide inventory collected after 2009 Typhoon Morakot in Renai Twonship, Nantou County. Approximately 57.0% of landslide cases induced by Typhoon Morakot in Renai Township were located in downslope locations, whereas 20.5% were located in upslope locations. The study created landslide susceptibility models by using logistic regression and the weight of evidence method. The accuracy of these two landslide models were 74.47% and 61.92%, respectively. The logistic regression– based landslide susceptibility model can predict most shallow landslide cases; however, it cannot predict groundwaterinduced landslides. Considering the landslide susceptibility and cost of buildings and roads, landslide loss caused by 24-h accumulated rainfall with the return period of 50, 100, and 200 years were estimated to be 1.18 × 109 , 2.40 × 109, and 3.87 × 109 dollars, respectively.本研究以南投縣仁愛鄉在 2009 年莫拉克颱風後崩塌目錄,建構仁愛鄉內之崩塌潛勢評估模式及 風險模式。仁愛鄉在 2009 年莫拉克颱風後之崩塌案例,有 57.0%位於下邊坡及 20.5%位於上邊坡,且崩塌規 模以小規模崩塌為主。崩塌潛勢評估模式建構分別以邏輯式迴歸法及證據權重法進行,兩種方法之正確率分 別為 74.47%及 61.92%,因此選定邏輯式迴歸法建構之崩塌潛勢評估模式,經現場比對後,該模式能預測出多 數淺層崩塌,但難以適用於地下水誘發的地滑型崩塌。最後將崩塌潛勢結果結合研究區域內之建物與道路成 本,套疊不同頻率年 24 小時累積降雨,獲得仁愛鄉在 50 年、100 年及 200 年 24 小時累積降雨事件下,可能 產生的損失風險值分別為 11.8 億、24.0 億及 38.7 億元

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