4 945 earthquake-induced mountain hazards in Wenchuan Earthquake were identified by field investigation and interpretation of remote-sensing images.GIS techniques were used to finish the statistical data analysis for the relationship between distribution of mountain hazards and environmental factors

including distance from middle faults

seismic intensity

and lithology.Research on the geological structure effects on the development of mountain hazards in earthquake was then conducted.The main results are summarized as follows:(1)The zonal distribution of mountain hazards was consistent with strike of middle faults and seismic energy was mainly released along the middle faults which caused the attenuation of energy obvious in the minor axis perpendicular to middle faults.The high density of hazards was distributed within the distance 12 km from middle faults.The density in hangingwalls of middle faults was obviously higher than that in footwalls because the middle faults belong to reversed thrust faults.The density appeared as reduction-increase-reduction in the footwalls of middle faults because of the combined action of middle faults and front faults which both belong to reversed thrust faults.(2)The mountain hazards

well developed at Ⅺ and Ⅹ seismic intensities

were obviously responsive with seismic energy

and about 99.29% of the mountain hazards were distributed in the areas where seismic intensity was greater than Ⅶ.(3)The density appeared in the order of calculous rocksolid rockloose rocksoft rock.Calculous rock was easy to disintegrate

especially the alternative distribution of calculous rock and soft rock by the effect of seismic wave.Many collapses were well developed in calculous rocks and landslides were well developed in loose rocks.