GIS-based earthquake-triggered landslide hazard zoning using contributing weight model |
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Authors: | Meng Wang Jianping Qiao Siming He |
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Institution: | (1) Geoscience Information Center, Korea Institute of Geoscience & Mineral Resources (KIGAM), 30, Gajung-Dong, Yusung-Gu, Daejeon, 305-350, Korea |
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Abstract: | Earthquake-triggered landslides have aroused widespread attention because of their tremendous ability to harm people’s lives
and properties. The best way to avoid and mitigate their damage is to develop landslide hazard maps and make them available
to the public in advance of an earthquake. Future construction can then be built according to the level of hazard and existing
structures can be retrofit as necessary. During recent years various approaches have been made to develop landslide hazard
maps using statistical analysis or physical models. However, these methods have limitations. This study introduces a new GIS-based
approach, using the contributing weight model, to evaluate the hazard of seismically-induced landslides. In this study, the
city and surrounding area of Dujiangyan was selected as the research area because of its moderate-high seismic activity. The
parameters incorporated into the model that related to the probability of landslide occurrence were: slope gradient, slope
aspect, geomorphology, lithology, base level, surface roughness, earthquake intensity, fault proximity, drainage proximity,
and road proximity. The parameters were converted into raster data format with a resolution of 25×25m2 pixels. Analysis of the GIS correlations shows that the highest earthquake-induced landslide hazard areas are mainly in the
hills and in some of the moderately steep mountainous areas of central Dujiangyan. The highest hazard zone covers an area
of 11.1% of the study area, and the density distribution of seismically-induced landslides was 3.025/km2 from the 2008 Wenchuan earthquake. The moderately hazardous areas are mainly distributed within the moderately steep mountainous
regions of the northern and southeastern parts of the study area and the hills of the northeastern part; covering 32.0% of
the study area and with a density distribution of 2.123/km2 resulting from the Wenchuan earthquake. The lowest hazard areas are mainly distributed in the topographically flat plain
in the northeastern part and some of the relatively gently slopes in the moderately steep mountainous areas of the northern
part of Dujiangyan and the surrounding area. The lowest hazard areas cover 56.9% of the study area and exhibited landslide
densities of 0.941/km2 and less from the Wenchuan earthquake. The quality of the hazard map was validated using a comparison with the distribution
of landslides that were cataloged as occurring from the Wenchuan earthquake. 43.1% of the study area consists of high and
moderate hazardous zones, and these regions include 83.5% of landslides caused by the Wenchuan earthquake. The successful
analysis shows that the contributing weight model can be effective for earthquake-triggered landslide hazard appraisal. The
model’s results can provide the basis for risk management and regional planning is. |
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Keywords: | Earthquake-triggered landslide GIS Contributing weight model Hazard zoning |
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