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| Titel |
The Influence of Geological Structures on the Initiation of Large Landslides: An Example from Hsiaolin Landslide Induced by Typhoon Morakot in 2009, Taiwan |
| VerfasserIn |
Ching-Weei Lin, Yen-Yen Li |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048109
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| Zusammenfassung |
| Hsiaolin landslide locates at Hsiaolin village in Kaoshuing county, southern Taiwan. The
landslide occurred at 06:17 on 9th of August. 450 peoples were buried in the landslide, and
over 27 millions m3 debris slides down and formed a landslide dam with a height
30 to 35 m above river channel to block Chishan River, and it broke at 7:00 on
August 9. Most of buildings in Hsiaolin village build on the river terraces with
elevation about 10 m above the river bed, and most of them were buried by the debris
of landslide, and the residuals were washed out by flooding when landslide dam
breakage.
Two folds (Hsiaolin syncline and unnamed anticline) and two faults (Chiahsien fault, and
Wulipu fault) are recognized in Hsiaolin area. All the structures trend in NNE-SSW except
for the WNW-ESE trending Wulipu fault. The Hsiaolin syncline which axis locates close to
the Hsiaolin village is an open, northern plunged syncline. The Chiahsien fault is composed
of several N-S trending, 40o-50o western dipping thrusts with minor amount of left-lateral
strike-slip motion. The Wulipu fault is a WNW-trending high angle fault with significant
right-lateral strike-slip motion.
The Hsiaolin landslide is recognized as a wedge type of failure. The failure wedge is mainly
formed by NNE-trending bedding plane of Pliocene-Miocene Tangenshan Sandstone and
WNW-trending high angle fractures which have similar attitude to that of the Wulipu fault.
The Chiahsien fault passes through the middle part of landslide. Field measurement shows
significantly increasing of fracture density at place nearby Chiahsien fault which provides
excellent path for fluid flow during heavy rainfall. Therefore, great fluid pressure associated
with decreasing the rocks strength in area nearby Chiahsien fault is proposed to be the main
factor to initiate the landslide in haevy rainfall. After failure initiation, landslide is enlarged
upward and a wedge type of failure occurred due to lose support in the middle of hill
slope. |
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