山地における災害被害の変化 : 2010年8月にインド北西部ラダーク管区で発生した集中豪雨被害をめぐる考察

Abstract

On August 5, 2010, local severe rain in Ladakh Province of northwestern India caused debris avalanches, which became an unprecedented catastrophe in which more than 150 people lost their lives and more than 400 went missing. These disasters originated primarily from Leh District in Ladakh Province; the heaviest damage occurred in the Choklamsar developing area located within the alluvial fan near the central city of the district. This study aims to clarify why considerable damage occurred, especially in the Choklamsar developing area, and to discuss transition of mountain disasters. Through an analysis of topographic maps and satellite images, it was found that most villages of Leh District are located away from the center of the alluvial fan because of the difficulty in obtaining water and the tendency to be easily damaged by debris avalanches. However, it is also ideal for the construction of large facilities such as army camps and schools due to plains and extended land. Thus, alluvial fans located near the central city have been developed for such facilities and residential sections of their working staffs after the 1970s; these form the Choklamsar developing area. The debris avalanche occurred there and caused extensive damage. Debris avalanches also occurred in other alluvial fans; however, because there were no residential sections there, human damage was minimized. Therefore, it is considered that the damage caused to the Choklamsar developing area reflects the change of land use form in mountain regions.