| dc.description.abstract | Owing to steep topography, complex geological environment, and improper land use, geologic disasters occur frequently in Taiwan, especially during typhoon seasons. Recently, the disaster of debris flow is especially severe. The purpose of this study is to understand the in influence of geologic zoning in debris-flow hazard and to improve the decision-making in hazard precaution. The study area is located between Tachi and Minchi, North Cross Island Highway, the Da-Han River watershed area, northern Taiwan. Space factors were chosen according to the characteristics of alluvial basins and streams. ANOVA analysis was then performed to choose debris flow-inducing factors with significant effect. Furthermore, multivariate analysis was used to compose debris flow-inducing factors, so as to discuss the influence of debris flow-inducing factors upon the determination of debris flow hazard streams. In addition, the debris flow hazard assessment is classified by combining multiple regression analysis with field studies. Results of the analyses displayed several debris flow-inducing factors in the risk assessment of debris flow. However, field investigation coped well with the analytic result in the sedimentary rock area, but for the metamorphic rock area, the chosen debris flow-inducing factors need to be corrected according to the characteristics of the area. The analytic procedures of the study still can be applied to difference geologic zones, although different parameters might be induced. Finally, the classification of debris flow hazard needs to be coped with the weighting of debris flow-inducing factors, in addition to the double-checking by field studies. The analytic results can be further compared with the debris flow data provided by the Soil and Water Conservation Bureau, to achieve the optimum correction for final results. | en_US |