Abstract: A large earthquake measured Ms=8.0 occurred on May 12, 2008 in Wenchuan County, Sichuan province. The earthquake caused a huge loss of lives and properties. At the same time, the earthquake casted numerous geological hazards such as landslides, sudden subsidence, falling rocks, unstable rock masses and debris flows. These geological hazards distributed along the main earthquake fault zones, main rivers, and valleys. Their features can be characterized as large quantity, high density and complicated types. The basic types of geological hazards are described in this paper. The main features of each were analyzed. It is concluded that, the geological hazards are still a high incidence in the last 3 to 5 years under the impact of rainfall and other adverse conditions. It will gradually become a relatedly low frequency 10 years later. The evolution trend of debris flow is that its activity intensity becomes from rapidly increase to progressively dormant. The active periods and dormant periods of debris flow alternate. The basic principles of postearthquake highway alignment selection are proposed in the paper. Some mitigation methods are also proposed for each geological hazard.

Key words: Wenchuan Earthquake, Highway Reconstruction, Geological Hazards, Mitigation Methods