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| Titel |
Landslides triggered by the 20 April 2013 Lushan earthquake, Sichuan Province, China : A case study in a region near the epicenter |
| VerfasserIn |
Chuan Tang, Ming Chang, Weile Li, Dandan Zhang, Tao Jia, Guochao Ma, Zhiyuan Zhou |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090951
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| Publikation (Nr.) |
 EGU/EGU2014-5212.pdf |
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| Zusammenfassung |
| Email: tangc707@gmail.com; tangc@cdut.edu.cn
Abstract: The 20 April 2013 Lushan earthquake with a magnitude of Ms 7.0 induced
widespread landsliding along the south segment of the Longmen Shan fault zone. This paper
presents a preliminary analysis of the characteristics of these co-seismic landslides
triggered in an area of 732 km2around the epicenter. A total of 755 landslides with a
total area of 1.414 km2 were identified from digital aerial photography taken after
the Lushan earthquake on April 22-28, 2013. About 56% of the landslides were
small (less than 1000 m2), whereas about 9 % were large (10,000 m2 or more). The
size of the landslides is in general much smaller than those which were triggered
by the Wenchuan earthquake. The most common types of landslides in the study
area were rock falls and shallow, disrupted landslides from steep slopes, typically
involving the top few meters of weathered bedrock and colluviums. During the seismic
shaking slope failures occurred much more often near river channels and along
roads.
In this study, the relation between the landslide distribution and five main factors: slope
angle, elevation, lithology, epicenter and fault proximity was analyzed. Our results show that
landslides induced by the Lushan earthquake mainly occurred on locations with slopes
between 20o and 50o, especially on slopes exceeding 30o. In addition, the areal frequency of
co-seismic landslides was the highest at elevations between 700 and 1300 m asl., with a
significant decrease in frequency at elevations above 1500 m. Over 95% of the landslides
occurred in three geologic units: Paleogene mudstones, Triassic dolomites, and Cretaceous
mudstones and sandstones while almost half of the total co-seismic landslide area
was triggered on slopes consisting of Cretaceous mudstones and sandstones. The
landslide area as a percentage of the total landslide area (LAP) and the landslide area
density (LAD) value tend to decrease with distance to the Shuangshi-Dachuan fault.
The LAP value within a distance of 4 km from the fault amounts to 71.5 %. The
location of the hanging wall and the footwall of the fault do not seem to have an
important effect on the landslide distribution in the Lushan earthquake area. This is in
contradiction to what has been reported in other earthquake areas such as the Wenchuan
area.
Key words: Lushan earthquake; co-seismic landslides; spatial distribution; landslide
concentration |
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