Earthquake-Induced Landslides1970 Yungay Peru, MW 7.9

1958 Lituya Bay, Alaska, MW 7.8

Lloyd S. CluffEarthquake Risk Management

Geosciences DepartmentPacific Gas and Electric

San Francisco

International Conference in Commemoration of the

10th Anniversary if the Chi-Chi EarthquakeSeptember 21 – 26, 2009

National Central University, Taiwan

Peru Earthquake 31 May 1970 MW 7.9

Nevado Huascran (elevation 6,400 m ) View Northeast from Huaraz

Yungay, Peru 1969, Before 1970 Earthquake, Pico Huascaran Elevation 6,768 m (22, 307 ft.) in Background

L. Cluff Photo

Yungay After Debris Avalanche Devastation

L. Cluff Photo 1970

Debris Avalanche Impact on Yungay

Cemetery hill

North Peak of Huascran Telephoto View of Debris Avalanche Source

Massive Granite Blocks From Pico HuascaranIn Yungay

Ranrahirca

Below Ranrahirca Near Rio Santa Valley

L. Cluff Photo 1970

Rio Santa Valley Floodplain Before Earthquake

L. Cluff Photo 1970

Rio Santa Valley Floodplain After Earthquake

Rio Santa Valley Floodplain Devastated ~160 Kmto Pacific Ocean Near Chimbote

L. Cluff Photo 1970

Diversion Dam Reported Destroyed (1970), However, Dam Was Undamaged

L. Cluff 1983

Yungay 1983 Rebuilding

L. Cluff Photo 1983

L Cluff 1988

View from Cemetery Hill, Yungay as it appeared in 1988

Plaza de ArmasNew construction

Nevado Huascaran

L Cluff 1988

1988 - Telephoto View East from Cemetery Hill

Plaza de Armas

Yungay 1983 Rebuilding

L. Cluff 1983

Yungay 1983 Rebuilding

L. Cluff 1983

Rio Santa Gorge View South

Proposed concreteDam 1983

Casma Before EQ

Casma After EQ

Shaking Performance of Unreinforced Masonry - Huaraz

L. Cluff Photo 1970

Huaraz School Survives Shaking Damage

L. Cluff Photo 1970

19587.81964

9.3

1958 Lituya Bay Fairweather Fault Earthquake Mw 7.8

L. Cluff Photo 1964

Fairweather Fault, View North 1958 MW 7.8

Looking North Along Strike of Fairweather Fault at Lituya Bay

524 m (1,720 ft.)

1958 Wave Trimline

1958 Tsunami Trimeline and Older Trimelines

M

K

H 1936 wave

J 1874 wave

1853 wave

Moraine ~ 1,000 years

Tree trimelines based on growth ring datingAverage recurrence ~ 26 years (elapsed time since 1958 = 51 yrs)

Lituya Bay, Alaska 1958 Photo of avalanche surge wave effects. Key: r = Avalanche sourcearea; rockslide dropped ~3,000 ft. (915 m); d = maximum wave height (1720 ft., 524 m)of tsunami surge onto spur of Gilbert Inlet; F = 3,600 ft., 1,097 m) wave inundation on northshore of bay; b = location of anchored fishing boat swept over land spit; a second fishingboat located near Bay entrance was sunk; e = a third anchored fishing boat that rode outtsunami wave. Modified after Miller (1958) and Miller (1960).

ee

bb

F

rr

dd

1958 Trimeline

Source

Max Run-up

InundationFishing boats ride out wave

X Fishing boat swept out to sea,two lives lost