Development of Rainfall Threshold Curve for Shallow Landslide Early-Warning Considering the Rainfall and Soil Parameters Uncertainties
|關鍵字:||坡地淺崩塌;定率模擬法;Trigrs;不確定性;預報可靠度;shallow landslide;deterministic;Trigrs;uncertainty;forecast reliability|
Rainfall induced landslide can cause huge loss of life and property. Establishment of an early warning system could offer a great help for the prevention and response of landslide related disasters. This study aims to develop a framework which enable the consideration of rainfall and soil parameters uncertainties to derive the rainfall threshold curves for shallow landslide under stipulated forecast reliabilities. To incorporate the uncertainties from rainfall, water retention curve, friction angle, cohesion, and initial groundwater level into landslide forecasting, the deterministic simulation approach along with the regression error analysis were adopted to derive the rainfall threshold curves for various lead-time and forecast reliabilities. The Mei-Liao Road located in Alishan Township, Chiayi County was the study site. Forty-nine historical hyetographs were collected among which 35 hyetographs were used to derive the threshold curve and the remaining 14 hyetographs were used to examine the accuracy. The examination results show that the forecast reliability for three hours lead-time is close to the stipulated value which indicates that the framework proposed is applicable. A discussion was also presented regarding the improvement of forecasting accuracy for 6, 8, and 12 hours lead-time.