LANDSLIDES, HABITABLE LAND, AND HAZARDS FOR TIBETAN VILLAGES IN JIUZHAIGOU NATIONAL PARK, SICHUAN, CHINA

While landslides create hazards for people in mountainous environments, in especially steep areas landslides can also create the only habitable land. Using Jiuzhaigou National Park, Sichuan, China as a case study, we investigate whether Tibetans preferentially located their villages on mass wasting deposits. Jiuzhaigou is located in the northern Min Shan at 2000-4700 m elevation, receives 661 mm of rain annually with the majority falling during the summer monsoon, and has average January temperatures of -1^oC and average July temperatures of 17^oC. Although mountainsides are steep, most are vegetated below tree line. The region is within the tectonically active eastern margin of the Tibetan Plateau and near the northern extent of the area damaged by the 2008 Wenchuan Earthquake. Tibetan villages in the Park have been progressively abandoned starting in the late 1980s when the Park was established. We identified former village sites and associated anthropogenic meadows from field work and on historical maps and satellite imagery. Interviews with local Tibetans confirm topographic analysis that shows Tibetans in Jiuzhaigou preferentially sited their villages in locations with long durations of winter sunlight (>200 hours/month in winter months), low slope angles (~20^o), mid-elevations (2200-2400 m), southerly aspects, and in the northern third of the Park which contains loess soils, on soils derived from loess. Most such preferred sites are on mass wasting features including slump-earthflows and rock avalanche deposits. Slump-earthflows range from relatively stable with early succession forests to actively deforming; some avalanche deposits actively receive new material from higher slopes. In Jiuzhaigou, there is a long history of hazardous events including recent incidents of house-destroying rock fall and an archaeological site buried 2,000 years ago by remobilized loess deposits on a still-active slump-earthflow. At most of the village sites we surveyed the potential for future mass wasting remains high, especially during the summer monsoon or large earthquakes. Thus, mass wasting in this region creates environments for people that are topographically favorable, but dangerous.