CATASTROPHIC LANDSLIDES TRIGGERED BY THE 2008

The 12 May Wenchuan earthquake killed at least 70,000 people and left nearly 5 million homeless. In the disastrous event, numerous landslides were triggered, especially as rapid and long runout landslides. For example, the earthquake sent about 2 million cubic meters of limestone rubble hurtling down a mountainside here, obliterating houses in Xiaojiaqiao village and creating a 70-meter-high dam on the Chaping River. These landslides traveled over extraordinarily large distances, and the dynamic regimes of emplacement are poorly constrained, because giant landslides are rarely seen in operation and because, apart from surface layers, only limited data are available about the nature of their deposits. Therefore, four kinds of rapid and long runout landslides were studied in detailed investigations, especially the largest landslides in volume, the longest in runout and landslides moving at the fastest speed, as well as the most disastrous landslides-dammed lake. The detailed information was described about these slides and debris flows, and their mechanisms were preliminarily analyzed. The paper thus aimed to describe key relations between landslide runout, drop height and volume, and so offer the prospect of improving hazard assessment and mitigation strategies in mountain districts.