以高解析度的DEM配合河流水力侵蝕模型，可將小尺度地形均衡特性因受構造線活動影響而變化的結果解析出來，是一套相當有效將地形均衡特性與構造線活動連結的分析工具。2009年8月7日至10日期間，莫拉克颱風帶來的豪大雨量，在台灣西南部高屏溪流域旗山溪與荖濃溪的中上游山區，引發大規模土石流形成災害地形。在土石流災害地形形成的三大主因中，地質條件：為何高屏溪流域旗山溪與荖濃溪中上游山區，會提供如此不僅是足夠而且是相當大量的堆積物，是否意味著這個區域在地形均衡與否的特性上，是屬於非均衡地形中的前均衡地形？為探討這個問題，本計畫將以旗山溪與荖濃溪兩個集水盆地的高解析度DEM為分析對象，應用河流水力侵蝕模型，解析其小尺度地形的均衡特性，並嘗試解釋其形成此次莫拉克風災土石流大量土石的潛在因素，以提供台灣西南部近期災害地形發生與潛勢的地形學解釋與預期。 Analysis of high resolution DEM using stream-power incision model can detect variation of steady-state characteristic of small scale topography influenced by local structure activities. Therefore, it’s an efficient analysis procedure of linking the steady-state characteristic of topography and the activities of local structure. From August 7 to 10 in 2009, the super heavy rainfall carried by Morakot typhoon caused the serious debris flow and formed the hazard topography near the midstream to upstream area of the Chishan and Laonung rivers in the the southwest Taiwan. Focusing to geology factor of debris flow occurrence, the midstream to upstream area of the Chishan and Laonung rivers provided a large amount of debris in the Morakot typhoon event. Does this mean that the area belongs to the pre-steady-state topography? For answering this question, this project will apply stream-power incision model to the high resolution DEMs of the Chishan and Laonung river basins to analyze steady-state characteristic of the small scale topography. Further, based on the results, this project will try to discuss the potential factors that caused the large amount of debris in the Morakot typhoon event, and provide geomorphologic explain and anticipation of the occurrence and potential to the recent hazard topography in the southwest Taiwan.
