Upload
harlin-media
View
223
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Slides for presentation given to High Mountains Adaptation Partnership in Huaraz, Peru on 13 July 2013.
Citation preview
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
■Previous studies on glacier hazards (Review) &
Satellite image analysis
(1) Geomorphological characteristics
(2) History of glacier hazards
■Suggestions
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
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)
Case 1:GLOF danger (1)
0.01 km2
0.04 km2
0.06 km2
0.05 km2
For comparison: Imja Glacier Lake ~1 km2
0.46 km2
Case 2:GLOF danger (2)
1.88 km2
0.18 km2
Case 3:Cascading glacial lake outburst
1.26 km2
0.13 km2 0.02 km2
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
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
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)
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
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
Development of Dasht Lake:
32,000 m2 (2002) ‘Guerrilla glacial
lake’ Repeatedly appeared
Rapidly enlarged
Short-lived
No surface outlet
Hazards assessment studies
(1) Schneider et al. (2010): danger evaluation of 209 villages
(2) Mergili and Schneider (2011): danger evaluation of 408 lakes
Glacier hazards expected
・Studied in six basins only. ・Glacier detachment, GLOF (debris flow?)
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
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
Epicenter distribution, Pamir Main Pamir Thrust (northern area)
Hindu Kush-Pamir seismic zone (SW area)
Gordon et al. (2012)
SW valleys in the Tajik Pamir: Landslides
20
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