Statistical Analysis the Distribution of Landslide Triggered by m 8.0 Wenchuan, China Earthquake of May 12, 2008

Abstract

Abundant landslides were triggered by Wenchuan earthquake. The paper mapped 4722 earthquake-induced landslides and used Geographic Information System to finish the statistical data about the occurrence of landslides correlating with environmental factors including distance from middle faults, lithology, altitude, river, and slope steepness. Because the seismic energy released along the middle faults and the attenuation of energy was obvious in minor axis, the zonal distribution of landslides was consistent with strike of middle faults and about 64.42% of landslides occurred within 20 km from middle faults of Longmenshan. As the middle faults and front faults both belonged to thrust faults, the impact of earthquake in hanging wall was higher than that in footwall. Therefore, the density of landslide in hanging wall of middle faults was obviously higher than that in footwall. As the release of seismic energy was restricted by landform and river, landslides were concentrative and consistent with the spatial distribution of rivers in the mountainous terrain. The scale effect of seismic acceleration was so intense in top of mountain with high difference in elevation along river that the origin of most landslides were in upside of slope. About 99.43% of landslides distributed in area where the seismic intensity was more than VII.