WIT Press


Debris Flow Hazard Mapping With A Random Walk Model In Korea

Price

Free (open access)

Paper DOI

10.2495/RISK100521

Volume

43

Pages

9

Page Range

627 - 635

Published

2010

Size

2879 kb

Author(s)

H.-J. Youn, C.-W. Lee & C.-S. Woo

Abstract

Recently, the sediment-related disasters, including landslides and debris flows, have been getting bigger due to the increasing intensity of typhoons and downpours that are affected by climate change. In particular, the debris flow is a severe disaster because it brings serious damage to villages and agricultural fields, as well as casualties. In order to reduce the damage caused by debris flows, this study carried out the predicting simulation of the affected area using a random walk model. The data of 12 debris flows were extracted from aerial photos taken in Inje and Pyeongchang counties, Gangwon province and Bongwha county, Gyeongbuk province, Korea in 2006 and 2008. In order to identify optimum parameter sets of the random walk model, these data of debris flows were used. There are three parameters, which are soil volume at a time, stop angle and inertia weight. These parameters are optimized when showing the highest correspondence rate, which means there is a comparison between a simulated sediment area and an actual sediment area after simulating 1,250 of combinations. The simulation was conducted to extract the optimum parameters, and the method of calculating the correspondence rate was developed to evaluate the value of parameters. The criteria for determining the danger and warning zone and the soil volume of collapse were prepared to make the debris flow hazard map. The debris flow hazard maps in Inje and Pyeongchang counties of Gangwon province and Bongwha county of Gyeongbuk province were made on the scale of 1:5,000. The hazard map will be helpful in deciding danger-prone zones and sites for soil erosion control works. Keywords: landslide, soil volume at a time, stop angle and inertia weight, correspondence rate.

Keywords

landslide, soil volume at a time, stop angle and inertia weight,correspondence rate