Evans Huaraz 2004

7/29/2019 Evans Huaraz 2004

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THE EXTRAORDINARY 2002 KOLKA

GLACIER-KARMADON ROCK/ICE

AVALANCHE AND SUBSEQUENTGLACIER/DEBRIS FLOW,

CAUCASUS MOUNTAINS, OSSETIA

REPUBLIC, RUSSIA

____________________________________________________

Stephen G. Evans,

University of Waterloo,

Waterloo, CANADA


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CASE HISTORIES AND HAZARD ASSESSMENT FOR

MOBILE,

VERY RAPID LANDSLIDES

1. POST-EVENT RECONSTRUCTION: INTERPRETATION OF

SEQUENCE, CHARACTERISTICS, AND GEOMETRY OF POST-

FAILURE PROCESSES (FIELD WORK, DIGITAL TERRAIN DATA,

REMOTE SENSING, SEISMOGRAMS, HYDRO-METEOROLOGICALDATA)

2. ATTEMPTS TO MODEL DYNAMIC BEHAVIOUR BASED ON (1)

3. COMPARISON TO SIMILAR EVENTS (ANOMALIES ?)

4. IMPLICATIONS FOR HAZARD ASSESSMENT


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INITIAL FAILURE

MECHANISM/VOLUME

ENTRAINMENT

VOLUME

CONFINEMENTCAPRICIOUS JUMP

DISTAL FLOW

RUNOUT 2

DEPOSITIONAL

FAN RUNOUT 1

ELEMENTS OF

MOBILE, VERY RAPID

LANDSLIDE

PROCESSES

PREVIOUSEVENT


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Date of event : September 20, 2002

THE CASE OF THE 2002 KOLKA-KARMADON EVENT, CAUCASUS

MOUNTAINS, RUSSIA


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03/Oct/2001 27/Sept/2002

AST

ER

FalseColou

rImagery


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In

ternationalSpa

ceStationPhoto

graph

Octobe

r19/2002


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4380 m


9/31image by Alexander Polkvoy


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16/31Image by Alexander Polkvoy


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WIDTH ~ 450 m

DEPTH ~ 275 m

SUPERELEVATION ~ 75 m


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SUMMARY GEOMETRY

Top of starting zone ~ 4350 m

Base of source slope ~ 3250 m

Elevation of Karmadon Gorge ~ 1320 m

Height of path to Gorge ~ 3030 m

Length of path to Gorge ~ 19 klm

Travel Angle to Gorge ~ 9 degrees

Average velocity ~ 91 m/s

Source Volume ~ 20 M cu m

Volume of Kolka Glacier ripped off ~ 110 M cu m

Volume of surficial material entrained in Genaldon

Valley ~ 20 M cu m

Total Volume ~ 150 M cu. m


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Earthquake-triggered 1970 Huascaran rock avalanche, Peruvian Andes


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1987 Parraguirre rock avalanche-debris flow, Chilean Andes

1959 Pandemonium Creek rock avalanche, Coast Mountains, B.C.


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N.B. Downstream limits of rock avalanche/debris flow not well

constrained in these cases

Comparative geometry of Kolka and similar historical

events since 1959

EVENT YEAR VOLUME

ESTIMATE

(M cu. m)

HEIGHT

(km)

LENGTH

(km)

H/L FAHRBOSCHUNG

(degrees)

Pandemonium 1959 7 2 8.6 0.23 13

Huascaran 1962 13 3.60 15.52 0.23 13Huascaran 1970 75-100 3.85 15.6 0.25 14

Parraguirre 1987 13 1.5 17 0.09 5

Kolka-Karmadon

2002 150 3.03 19 0.16 9


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CONCLUSIONS and IMPLICATIONS 1

1. Exemplifies catastrophic potential in glacierised

mountains

2. Comparable to 1959 Pandemonium Creek

(Canada), 1962 & 1970 Huascaran (Peru) and

1987 Parraguirre (Chile) events

3. Average velocity highly anomalous

4. Mechanism of Kolka Glacier entrainment still notclear.

5. Evidence of previous events

6. Potential exists in other valleys in the region with

glaciers and steep slopes in upper reaches

7. Difficulty in characterising true landslide geometry

(source vol., entrainment and distal flow limits)


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CONCLUSIONS and IMPLICATIONS 2

1. Initial volume and failure mechanism often quite

difficult to establish in high mountains2. Post-failure behaviour may involve and may be

influenced by entrainment

3. Entrainment may be massive.

4. Difficulty in characterising true landslide geometry

(entrainment and distal flow limits)

5. 3 and 4 pose modelling problems; true prediction (as

opposed to retrodiction) is possibly far off.

6. Hazard assessment for risk evaluation is conditioned

by this uncertainty

7. Previous events should be a very substantial warning

to the landslide specialist

_____________________________________


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ACKNOWLEDGEMENTS

1. NATO

2. Ministry of Natural Resources (Russian

Federation)

Oleg Zerkal

3. Igor Galushkin, Alexander Polkovoy, Elena

Pigareva, Andrei Goncharov, Olga Tutubalina


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Evans Huaraz 2004