Transcript
Page 1: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

GLOF and glacier-related hazards and risk in Tajikistan

Faculty of Environmental Earth Science Tetsuya Komatsu and Teiji Watanabe

Managing Climate Change in High Mountain Glacial Watersheds, Huaraz, Peru, 11-14July 2013

Page 2: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

■Previous studies on glacier hazards (Review) &

Satellite image analysis

(1) Geomorphological characteristics

(2) History of glacier hazards

■Suggestions

Page 3: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

Annual precipitation

(UNEP, 2002)

Settlements: on the younger terrace or on the alluvial fan/cone (Watanabe, 2000)

Misau located on an alluvial cone

L: Lenin Peak (7,143 m), I: Ismoil Somoni (7,495 m), KM: Karl Marx (6,723 m) Darjomch village (ca. 2,170 m) located on a young (3–5 ka?) river terrace (5 – 38 m higher from the river)

Previous studies

Page 4: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

Institute of Geography, USSR Academy of Sciences ・6,730 glaciers(7,403 km2). ・630 glaciers have ‘surging’ history ・20 surge glaciers advanced their terminus.

Kotlyakov et al. (2010)

Previous studies

BOKU University’s group: GLOF studies in the SW part of Tajik Pamir ・Identified 172 glacial lakes (≥2,500 m2) ・Most were formed after 1968

Mergili and Schneider (2011), Mergili et al. (2012)

Page 5: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

Case 1:GLOF danger (1)

0.01 km2

0.04 km2

0.06 km2

0.05 km2

For comparison: Imja Glacier Lake ~1 km2

Page 6: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

0.46 km2

Case 2:GLOF danger (2)

1.88 km2

0.18 km2

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Case 3:Cascading glacial lake outburst

1.26 km2

0.13 km2 0.02 km2

Page 8: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

2570 m asl

4080 m asl

5140 m asl

Short distance from glacier to settlement: 5 – 20 km

ca. 600 m

Simple application of early warning may not be appropriate

Page 9: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

Confirmed glacier-related hazards (1)Hazard by glacier surge (2 glacier detachments, 2 valley blocking) (2)Hazard by GLOF (1 case)

Ravak Glacier 20 July 1967

200 m advanced

Dasht Lake 7 Aug. 2002

Bear Glacier 1963, 1973, 2011

Didal Glacier 1974

Blue: Surge glacier Yellow: Debris-flow hazard by surging Red: GLOF & glacial-lake hazard by surging

Page 10: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

Glacier surge and GLOF: Bear Glacier NASA Earth Observatory (2011)

・Surged in 1951, 1963, 1973, 1989, 2001 and 2011. ・The surged terminus blocked the valley in 1963, 1973, 1989 & 2011. ・The dammed lake damaged infrastructure downstream.

Base image and the termini on 2 May & 3 June: NASA Earth Observatory (2011)

Page 11: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

GLOF: The Dasht 2002 event •  Outburst of a glacial lake (4,400 m, 0.03 km2) on 7 August 2002.

•  Reached Dasht village (2,600 m), 10.5 km downstream, in 45 minutes. Killed 25 village people.

Photo:Schneider and Mergili (2010)

2 km

Shakhdara Valley

Page 12: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

ca. 200 m

Mergili et al. (2012): GLOF occurred by collapse of

ice-cored moraine in 2002

Dasht lake

Google Earth image: 31 August 2008

Page 13: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

Development of Dasht Lake:

32,000 m2 (2002) ‘Guerrilla glacial

lake’ Repeatedly appeared

Rapidly enlarged

Short-lived

No surface outlet

Page 14: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

Hazards assessment studies

(1) Schneider et al. (2010): danger evaluation of 209 villages

(2) Mergili and Schneider (2011): danger evaluation of 408 lakes

Page 15: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

Glacier hazards expected

・Studied in six basins only. ・Glacier detachment, GLOF (debris flow?)

Page 16: Teiji Watanabe: GLOF and glacier-related hazards and risk in Tajikistan

Mergili and Schneider (2011): seven classes of outburst danger

408 lakes

Extremely high: 0

Very high: 6

High: 34

Especially dangerous: downstream of 3 lakes

Mergili and Schneider (2011)

0.46 km2 0.33 km2

0.15 km2

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Considerations needed

□Missing area of studies •  Inventory of glaciers for the whole area

□Regular monitoring •  Hanging glaciers: crack •  Surge-type glaciers: surging •  Glacial lakes: development (guerrilla glacial lakes)

・Repeat appearance, rapid enlargement, & short life

・Tien Shan: 2.5 months from lake appearance to burst

□Mitigation •  Consideration of settlement locations and distance

to the source area

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Epicenter distribution, Pamir Main Pamir Thrust (northern area)

Hindu Kush-Pamir seismic zone (SW area)  

Gordon et al. (2012) 

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SW valleys in the Tajik Pamir: Landslides

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New monitoring

Ultra-micro satellite, <50 kg

http://www.astro.mech.tohoku.ac.jp/RISING-2/

  Frequency Resolution Data handling Cost

Helicopter ○ (weather dependent) ○ × ×

Landsat, ASTER × (16-day cycle) △ (15 m) ○ ○

Ikonos × (11-day cycle) ○ (~2 m) ○ ×

Ultra-micro satellite ○ (1-day cycle) ○ (~5 m) ○ ? (USD 1 million


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