| dc.description.abstract | Debris-flows classification is very important for hazards mitigation. Based on different purpose, the potential streams of debris flow have been classified as different categories. This research set up a systemic categorised way by using potential streams of debris flow investigation result form Central Geological Survey, MEOA. Three areas, Lugu, Sansia, and Tungshih, were selected as a study area. According to the analysis result, every debris flow can be characterized by hydrology, geology and deposit characteristics. Most of Taiwan’s potential streams of debris flow are non-cohesive. In addition, this research suggested a velocity index which consider the drainage area, stream slope and width. A high valure of velocity index represent a high endanger degree. Similarly, the bigger grain size of debris, the largger damage it might induce. There are 275 potential streams of debris flow belong to block category which need to be considered before planning the debris flow harzad mitigation project. In this research, we propose the activity of debris flow canbe classified by landslide area and deposition ratio. 28 potential streams of debris flow were classified as high activity potential streams of debris flow.
According to the debris-flows classification result of Luku and Sansia, it is clearly that the important geology events(Chi-Chi earthquake) make a influence of the activity of debris. Consequently, the avtivity of debris flow should be changed with the variation of landslide and deposition of debris. | en_US |