Co-seismic landslide topographic analysis based on multi-temporal DEM—A case study of the Wenchuan earthquake

Zhikun Ren,Jinhui Yin,Fuchu Dai,Huiping Zhang,Zhuqi Zhang

doi:10.1186/2193-1801-2-544

Abstract

Hillslope instability has been thought to be one of the most important factors for landslide susceptibility. In this study, we apply geomorphic analysis using multi-temporal DEM data and shake intensity analysis to evaluate the topographic characteristics of the landslide areas. There are many geomorphologic analysis methods such as roughness, slope aspect, which are also as useful as slope analysis. The analyses indicate that most of the co-seismic landslides occurred in regions with roughness, hillslope and slope aspect of >1.2, >30, and between 90 and 270, respectively. However, the intersection regions from the above three methods are more accurate than that derived by applying single topographic analysis method. The ground motion data indicates that the co-seismic landslides mainly occurred on the hanging wall side of Longmen Shan Thrust Belt within the up-down and horizontal peak ground acceleration (PGA) contour of 150 PGA and 200 gal, respectively. The comparisons of pre- and post-earthquake DEM data indicate that the medium roughness and slope increased, the roughest and steepest regions decreased after the Wenchuan earthquake. However, slope aspects did not even change. Our results indicate that co-seismic landslides mainly occurred at specific regions of high roughness, southward and steep sloping areas under strong ground motion. Co-seismic landslides significantly modified the local topography, especially the hillslope and roughness. The roughest relief and steepest slope are significantly smoothed; however, the medium relief and slope become rougher and steeper, respectively.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-544) contains supplementary material, which is available to authorized users.

Highlights

It has been commonly accepted that steep topography are of high landslide frequency in active orogenic region
The co-seismic landslides usually occurred in active orogenic regions, which are one of the major secondary nature hazards related to strong earthquakes (Harp and Jibson 1996; Gallousi and Koukouvelas 2007; Owen et al 2008; Ren and Lin 2010; Dai et al 2011a)
We use the open accessed strong motion records to analyze the relationship between Wenchuan earthquake triggered co-seismic landslides and the peak ground acceleration (PGA) distribution, which is distributed by CSMNC (China Strong Motion Networks Center), IEMCEA (Institute of Engineering Mechanics, China Earthquake Administration)

Summary

Introduction

It has been commonly accepted that steep topography are of high landslide frequency in active orogenic region. The co-seismic landslides usually occurred in active orogenic regions, which are one of the major secondary nature hazards related to strong earthquakes (Harp and Jibson 1996; Gallousi and Koukouvelas 2007; Owen et al 2008; Ren and Lin 2010; Dai et al 2011a). Co-seismic landslides even produce more serious human loss and damages than the earthquake itself. The coseismic landslides have fundamental influence on human life and seismic design of buildings etc. It has been noticed that transportation and deposition of the landslide materials will have fundamental impact on the topographic have been analyzed in detail (Dai et al 2011a). We use the open accessed strong motion records to analyze the relationship between Wenchuan earthquake triggered co-seismic landslides and the peak ground acceleration (PGA) distribution, which is distributed by CSMNC (China Strong Motion Networks Center), IEMCEA (Institute of Engineering Mechanics, China Earthquake Administration)

Methods

Findings

Discussion

Conclusion