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