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| Titel |
GIS-based analysis of 1933 Diexi Landslides and dam breach on the Min River, Sichuan, China |
| VerfasserIn |
Song Ling, Stephen G. Evans |
| 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 |
250096914
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| Publikation (Nr.) |
 EGU/EGU2014-12446.pdf |
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| Zusammenfassung |
| Due to complex tectonic and geomorphologic factors, the Tibetan Plateau and its surrounding
areas, are particularly prone to landslides. Rivers have deeply cut into bedrock, forming
narrow valleys that are especially prone to landslide damming. Numerous landslide damming
and subsequent dam breaching events are recorded from the region in historical documents
and the geosciece literature; these include events at the Dadu River (1786), Diexi (1933),
Tanggudong (1967), Yigong (2000), and Tangjiashan (2008). We report the results of a
GIS-based analysis of earthquake-generated landslide dams at Diexi. The Diexi
Earthquake (M=7.5) occurred on August 25, 1933 and induced a series of giant
landslides along the Min River, some of which blocked the river and formed three
large landslide lakes. The landslide dam located furthest downstream breached
on October 9, 1933, 45 days after the earthquake. The outburst flood resulted in
huge damage to the downstream area killing 2,423 people, one of the most serious
landslide-related disasters in China during the 20th Century. In the present work,
GIS analysis is applied to the Diexi Landslides, based on a review of historical
documents and previous studies, data collected during field work, and remote sensing
and SRTM-3 digital terrain data. We attempted to determine the precise locations
of the 1933 landslides and measured dam height, cross-section area, and volume
of the damming landslides. Due to the lack of topographic data before the 1933
earthquake, data of the landslide lakes, including maximum water elevation and total
impounded volume can only be estimated. Using credible water levels and inferred
submerged topography we calculate an outburst volume for the 1933 event. Moreover,
cross-sections are made for both the damming area and the Min River downstream in
order to make a general assessment of the damage due to the subsequent flood.
Maximum flood discharge is estimated by regression equations. The two remaining
lakes on the Min River have experienced a slight water level decrease after over
80 years of outlet erosion. Despite this, these two lakes are considered to be safe. |
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