Earthquake induced landslides

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Presentaations given in Christchurch, Wellington and Auckland in August 2008

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Earthquake induced landslides lessons from Taiwan and Pakistan : 

Earthquake induced landslides lessons from Taiwan and Pakistan David Petley 26th August 2008 http:daveslandslideblog.blogspot.com

2007 fatal landslides : 

2007 fatal landslides

2008 fatal landslides (to end of July) : 

2008 fatal landslides (to end of July)

Worldwide fatal landslides in 2007 by size : 

Worldwide fatal landslides in 2007 by size

Slide 6: 

Diagrams: Bilham and Yu 2000 The morphology of thrust faulting in the 21 September 1999, Chichi, Taiwan earthquake. Journal of Asian Earth Sciences, 18, 351-367. Chi-Chi earthquake 21st September 1999 Mw = 7.6 Depth = 8 km

Slide 7: 

Kashmir earthquake 8th October 2005 Mw = 7.6 Depth = 10 km Images: Roger Bilham and GSI Japan

Wenchuan earthquake : 

Wenchuan earthquake 12th May 2008 Mw = 7.9 Depth = 8 km Images: Fawu Yang, DPRI Kyoto

Chi-Chi landslides : 

Chi-Chi landslides >22,000 landslides in total ; 9,272 landslides > 625 m2 ; Total landslide area 128 km2

Distribution of landslides triggered by the earthquake : 

Distribution of landslides triggered by the earthquake Khazai and Sitar 2003

Landslide distribution and E-W PGA : 

Landslide distribution and E-W PGA Khazai and Sitar 2003

Slide 12: 

Kashmir landslides 2252 landslides > 625 m2

Hattian landslide : 

Hattian landslide

GSI Japan landslide map from SPOT imagery : 

GSI Japan landslide map from SPOT imagery

Kashmir modelled iso-acceleration contours for soft ground (Omer 2007) : 

Kashmir modelled iso-acceleration contours for soft ground (Omer 2007)

Area affected by landslides (Based on Keefer 1984) : 

Area affected by landslides (Based on Keefer 1984) 9.0 6.5 Magnitude 1 4.0 100 10k 500k Area affected by landslides (km2) Kashmir Taiwan

Kashmir and Taiwan earthquake landslides : 

Kashmir and Taiwan earthquake landslides

Landslide distance from fault (Sato et al. 2007)Inset: Taiwan data (Meunier et al. 2007) : 

Landslide distance from fault (Sato et al. 2007)Inset: Taiwan data (Meunier et al. 2007) Number of landslides 600 500 400 300 200 100 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Distance from fault rupture (km) 83% of landslides within 2 km of fault 90% on hanging wall Chelungpu Fault N-NW S-SE Number of landslides -10 0 10 20 30 40 50 Distance from fault rupture (km) 1200 800 400 0 -10 -20 Elevation (km) 3 2 1 0 Depth (km)

Topographic influence(Murphy et al. 2002) : 

Topographic influence(Murphy et al. 2002)

Comparison: average and 2004 to 2006GPCC (rain gauge) data : 

Comparison: average and 2004 to 2006GPCC (rain gauge) data

Precipitation deficit (mm) : 

Precipitation deficit (mm)

Tachia (Techi) River Valley : 

Tachia (Techi) River Valley

Taiwan rainfall – Typhoon Mindule : 

Taiwan rainfall – Typhoon Mindule

Slide 31: 

2000 2004

Lin et al. 2007: Choushui River : 

Lin et al. 2007: Choushui River

Response upstream of the affected area – Sung Mao : 

Response upstream of the affected area – Sung Mao

Slide 34: 

Response downstream of the affected area – Pailau Bridge

Pai-Lau bridge : 

Pai-Lau bridge

Chinan, Wu-Hsi : 

Chinan, Wu-Hsi

Long term trend at Pai-Lau Bridge : 

Long term trend at Pai-Lau Bridge

Before the earthquake : 

Before the earthquake Hydroelectric scheme inlets

November 2006 : 

November 2006

Downstream consequencesKukuan after Typhoon Mindule in 2001 : 

Downstream consequencesKukuan after Typhoon Mindule in 2001

Slide 41: 

Downstream consequencesKukuan after Typhoon Toraji in 2004

Slide 42: 

Downstream consequencesKukuan in 2006

Costs of landslides and sediment productionTachia River Valley : 

Costs of landslides and sediment productionTachia River Valley Total costs to date = £384 million Required rebuild costs of road = £100 million Consisting of: Landslide induced sediment production induced damage to HEP: £150 million Additional power generation needs: £160 million Initial repair of road: £26 million Additional agricultural transportation costs to date: £48 million But to date only 15% of the displaced sediment has been released

Slide 45: 

Area hit by strong typhoon in July 2008 Further massive landslides

Conclusions : 

Conclusions Presentation at: http:daveslandslideblog.blogspot.com