ML 7.3MW 7.6

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Chi-Chi epicenter

Landslides

Jiufengershan landslideJiufengershan landslide

Geological contextGeological context

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Geological SectionGeological Section

1.5 km × 40~60mElevation difference: ~ 500mDip angle: 20°

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Monocline ?Monocline ?

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Cut-and-fill volumeCut-and-fill volume

Cut: 42.1 x 106 m3

Fill: 50.5 x 106 m3

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Tsaoling landslideTsaoling landslide

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TimeTriggered by

Landslide process

Slide volume (km3)

Dam height (m)Effects

1862Earthquake

(ML=6-7) Landslide formation of a dam

1898 Rainfall (?) Landslide dam broke

1941Earthquake

(ML=7.1) 0.10-0.15 70-14036 persons killed and formation of a dam

1942Rainfall (776mm)

0.15-0.20 140-1701 persons killed and increased landslide dam

1951Rainfall (770mm)

0.120 140-200137 persons killed and broke landslide dam

1979

Rainfall (327mm)

0.026 90 Landslide formation of a dam

Rainfall (624mm)

0.040 Landslide dam broke

1999Earthquake

(ML=7.3) 0.126 4539 persons killed and formation of a dam

Historical events in Tsaoling

Historical events in Tsaoling

Geological mapGeological map

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Stratigraphic column and profile

Stratigraphic column and profile

DTMsDTMs

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Geological profileGeological profile

Sliding area

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Cut-and-fill volume1999 vs.2003

Cut-and-fill volume1999 vs.2003

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Cut-and-fill volume2003 vs.2007

Cut-and-fill volume2003 vs.2007

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Retreat of the scarpRetreat of the scarp

main scarpmain scarp

730m

1998199920032007

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Retreat of the scarpRetreat of the scarp

155m

minor scarpminor scarp

1998199920032007

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Retreat of the scarpRetreat of the scarp

38m

1998199920032007

lateral scarplateral scarp

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Retreat of the scarpRetreat of the scarp

20032007

280m

upstream

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Retreat of the scarpRetreat of the scarp

240m

downstream

20032007

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B

ED

A

C

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