RISK ASSESSMENT OF COMPLEX DISASTER CAUSED BY DEBRIS FLOW

Abstract

 Recent years, heavy rainfall disasters have been more frequently occurring due to climate changes, and the damage reports from complex disasters caused by debris flows increased. In this study, debris flow simulations were conducted at 171 locations along railroads in Yamaguchi Prefecture to evaluate the risk of complex disasters in which debris flow can flow into railroads and rivers based on sediment deposited thickness. As a result, there were many places where sediment flowed into outside the debris flow hazard area in the simulation. In addition, the railroad damage risk was higher in the places where the railroad was located at the foot of the mountains and where debris flows contacted the railroad after long distance move. The results also suggest that the risk of complex disaster can be assessed by a statistical model with topographic features that correlate with the complex disaster risk estimated from the simulations.