11:15 AM - 11:30 AM
[HDS07-09] Mobility of earthquake-induced tephra deposit landslides: Error factors in elevation differential analysis and their impact on mobility evaluation
Keywords:landslide mobility, equivalent coefficient of friction, tephra deposit, 2016 Kumamoto earthquake, elevation differential analysis
Long-runout landslides comprising volcaniclastic materials have been widely observed in the world. Coseismic landslides of fallout tephra deposits are typical of such landslides; they often show exceptionally high mobility because they occur on gentle slopes, with equivalent coefficients of friction (H/L ratios) as low as the coefficients of debris avalanches with larger volumes (> 106 m3). To examine the mobility of displaced mass comprising tephra deposits and predict the landslide runout distance, precise measurement of landslide volume and geometry is the first requirement. Here, the author reports an analysis result of tephra deposit landslides induced by the 2016 Mw7.0 Kumamoto earthquake using high-resolution, multi-temporal DEMs developed for the periods before and after the earthquake.