The study paper highlights the occurrence of flow-like landslides triggered by heavy rainfall in Nepal and Shikoku, Japan. It specifically mentions two incidents: the landslides that occurred in the southern hills of Kathmandu, Nepal, in July 2002, and the extensive damage caused by strong typhoons in northern Shikoku, Japan, in August, September, and October 2004. The document provides a brief overview of the incidents and recommendations based on field investigations.
During the investigations, the geotechnical properties of landslide materials were determined in the laboratory. The volume of material involved in some of the flows was calculated as per average thickness of the soil cover and area of failure. Likewise, rainfall threshold value for Kathmandu and Northern Shikoku is also evaluated. From the field investigations, it is recommended that human habitation at the foot of hills should be legally regulated by the government to reduce death from flow-like landslides triggered by torrential rainfall. It also recommends that landslide hazard maps need to be quantified to include landslide risk assessment and management for flow like landslide also which help to develop early warning systems for flow-like landslide disasters.
Ranjan Kumar Dahal, Shuichi Hasegawa, Minoru Yamanaka & Katsuhiro Nishino