近年來,氣候之異常變遷常引發嚴重災害,因此台灣逐漸重視山區崩塌情況及後續可能發生崩塌潛勢之分析,其中最直接關係的是崩塌塊體可能對聚落影響之程度,故為了解崩塌之特性及界定影響崩塌土方運移距離之因素為何,特進行此研究。 本文研究區域涵蓋南化水庫、旗山溪流域及荖濃溪流域之集水區,主要以莫拉克颱風災害前後之新生崩塌區域為崩塌地形狀繪製之主要區域。在新生崩塌區域之判釋先以高解析度之航空照片進行綠度指數(Greeness)計算出裸露地以作為崩塌裸露區域之初步判釋,再輔以2米之高精度數值高程模型(DEM)資料之前後變異區域,去除舊有崩塌地及河道以進行崩塌地地形幾何形狀之人工編修。在崩塌地幾何形狀之繪製方面,本研究採用之地形幾何因子有崩塌塊體之運移距離、崩塌坡面之寬、高程差、面積、體積。因此本研究先針對莫拉克颱風所造成之新生崩塌地形幾何因子進行對應關係之探討,其能經由塊體運移距離與其他因子之相關性,進而了解土方塊體移動是否受幾何形狀因子之影響。再比較分析與其他土石流等不同運移機制之異同,進而可為土方移動之研究做一統整分析。 研究成果顯示,利用高精度之DEM能更精確計算地形變異量,提供較詳細之資料品質以進行崩塌運移距離與其他幾何因子關係之探討。經由集水區內新生崩塌之崩塌體積與崩塌面積之關係以及崩塌體積與崩塌運移之關係可得知,面積越大或崩塌體積越大,塊體移動之距離越長,另外也可由不同災害類型對應運移距離之比較發現崩塌之塊體移動長度會因崩塌夾帶材料之不同而有所差異。
Recently, climate change cause serious disaster in mountain area. Hence, people gradually concern about condition of landslide in mountain area and consequence analysis of landslide potential. The most important relationship is to estimate the affect between landslide mass and village. The study focus on the characteristic of landslide and the factors affect landslide mass travel distance. Study area includes catchment of Nanhua Reservoir, Chishan River, and Laonong River. In this research take newly landslide area before and after Typhoon Morakot as landslide area. In the delineation of newly landslide area using high resolution Aerial-photos and digital elevation model (2 meter resolution) to calculate Greeness index and correct spatial variation area before and after Typhoon Morakot. In this study using travel distance of landslide mass, width of landslide slope, elevation deviation of landslide top and bottom, landslide area, and landslide volume as affect factors. In order to understand travel distance of landslide mass is affect by the other factors or not. The relationship of travel distance of landslide mass and other affect factors was analyzed and compare with travel distance of landslide mass triggered by the debris flow. The results show that high resolution digital elevation model supplies more detail data quality and more precisely calculate the volume of terrain variation. From the relationship between landslide volume and travel distance of landslide mass to obtain the bigger the landslide volume or area the further of travel distance of landslide mass. In the comparison of difference type of sediment disaster and travel distance of landslide mass show that travel distance affect by the material of landslide mass.