1. International Conference in Commemoration of the
10th Anniversary if the Chi-Chi Earthquake
September 21 – 26, 2009
National Central University, Taiwan
Earthquake-Induced Landslides 1970 Yungay Peru, MW Lituya Bay, Alaska, MW 7.8
Lloyd S. Cluff
Earthquake Risk Management
Geosciences Department
Pacific Gas and Electric
San Francisco

2. Peru Earthquake 31 May 1970 MW 7.9

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

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

5. Yungay After Debris Avalanche Devastation
L. Cluff Photo 1970

6. Debris Avalanche Impact on Yungay
Cemetery hill

7. North Peak of Huascran Telephoto View of Debris Avalanche Source

8. Massive Granite Blocks From Pico Huascaran
In Yungay

9. Ranrahirca

10. Below Ranrahirca Near Rio Santa Valley
L. Cluff Photo 1970

11. Rio Santa Valley Floodplain Before Earthquake

12. Rio Santa Valley Floodplain After Earthquake
L. Cluff Photo 1970

13. Rio Santa Valley Floodplain Devastated ~160 Km
to Pacific Ocean Near Chimbote
L. Cluff Photo 1970

14. Diversion Dam Reported Destroyed (1970), However, Dam Was Undamaged
L. Cluff 1983

15. Yungay 1983 Rebuilding
L. Cluff Photo 1983

16. View from Cemetery Hill, Yungay as it appeared in 1988
Nevado Huascaran
Plaza de Armas
New construction
L Cluff 1988

17. 1988 - Telephoto View East from Cemetery Hill
Plaza de Armas
L Cluff 1988

18. Yungay 1983 Rebuilding
L. Cluff 1983

19. Yungay 1983 Rebuilding
L. Cluff 1983

20. Rio Santa Gorge View South
Proposed concrete
Dam 1983

21. Casma Before EQ
Casma After EQ

22. Shaking Performance of Unreinforced Masonry - Huaraz
L. Cluff Photo 1970

23. Huaraz School Survives Shaking Damage
L. Cluff Photo 1970

24. Fairweather Fault Earthquake Mw 7.8
1958 Lituya Bay
Fairweather Fault Earthquake Mw 7.8
1958
7.8

25. Fairweather Fault, View North 1958 MW 7.8
L. Cluff Photo 1964

26. Looking North Along Strike of Fairweather Fault at Lituya Bay

28. 1958 Wave Trimline
524 m (1,720 ft.)
FIGURE photo showing maximum tsunami wave surge height of 524 m (1,720 ft.) modified after Miller (1958)

29. 1958 Tsunami Trimeline and Older Trimelines
Moraine ~ 1,000 years K
1853 wave J
1874 wave H
1936 wave
FIGURE 12. North shore of Lituya Bay showing multiple wave trimlines as evidence for past debris avalanche waves: H = 1936 trimline, J = 1874 trimeline, K = 1853 or 54 trimline, and M = Glacial Moraine trimline. Photo 1954, Miller (1958)
Tree trimelines based on growth ring dating
Average recurrence ~ 26 years (elapsed time since 1958 = 51 yrs)

30. X Fishing boat swept out to sea,
Source r
Max Run-up d
1958 Trimeline
Inundation
Fishing boats ride out wave F e
FIGURE 13. Lituya Bay, 1958 Photo of avalanche tsunami wave effects. Key: r = Avalanche source area; 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 north shore of bay; b = location of anchored fishing boat swept over land spit; a second fishing boat located near Bay entrance was sunk; e = a third anchored fishing boat that rode out tsunami wave. Modified after Miller (1958) and Miller (1960).
X Fishing boat swept out to sea,
two lives lost b
Lituya Bay, Alaska 1958 Photo of avalanche surge wave effects. Key: r = Avalanche source
area; 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 north
shore of bay; b = location of anchored fishing boat swept over land spit; a second fishing
boat located near Bay entrance was sunk; e = a third anchored fishing boat that rode out
tsunami wave. Modified after Miller (1958) and Miller (1960).

31. FIGURE 9.Map of Lituya Bay southeastern Alaska, Miller (1960)