本研究於苗栗縣三義鄉火炎山一號坑，建立現地土石流影像監測系統及利用無人機拍攝空拍照片建立現地模型進行運動特性分析，包括流動歷程、地貌變化、土石流龍頭平均速度、陣流特性、流深分析、流動路徑與長度、現地不動點分析、土石流沖刷淤積量、斷面坡度與高程分析。歷次土石流的運行受河道坡度調控，低坡度河道為土石流堆積之主要區段，並成為下次土石流事件發生時之主要料源之一。本研究彙整 2016年至 2023年間各場事件之降雨量料，有效累積降雨強度(含前期降雨)與土石流流動距離間有高度正關聯性。

In this study, the debris-flow monitoring system was established at the Gully 1 of Huoyan Mountain, San Yi Township, Miaoli County. Aerial images were captured using drones (UAV) to create local models for analyzing the dynamic characteristics of debris-flow events. The analysis covered various aspects including flow dynamics, average velocity of the surging fronts, geomorphological characteristics of lateral levees and channel beds. The movements of gravelly debris flows are mainly controlled by the riverbed gradient, with low-gradient riverbeds serving as major deposition zones for debris flow snouts and being fluidized during subsequent surging events. Through the analysis of rainfall data of various debris-flow events during 2016 – 2023, a correlation between effective cumulative rainfall intensity (including the pre-event rainfall) and the runout distance of debris flows is found in this study.

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