Institute of Geology,
Earthquake Engineering
and Seismology
Academy of Sciences
of the Republic of Tajikistan
Prof. Dr. Farshed H. Karimov
Dynamics of Large Mountain-Valley Glaciers’ Flow in Tajikistan
Berlin - 8-10 December 2014
Tajikistan: Square ≈143 000 km2
Population ≥ 7 mln.
Mountains - 93% (Pamir, Tan-Shan…)
Waters - glaciers, lakes, rivers,
reservoirs, underground
Climate - sharply continental
rural
27.2 %
urban
rural
27.2
Glaciers in Tajikistan – the facts [1,2]
• Glaciers cover 6% of the Tajikistan territory.
• Glaciers are the main source feeding the rivers in Tajikistan,
composing about 60% of the Middle Asia water resources.
• Climate global changes made 20 km3 shortage of waters
during the XX century (of 600 km3).
• For the last 50 years about 30% of glaciers’ square shortage.
• More than 50 glaciers disappeared
Main causes of global climate changes:
• Industrial and anthropogenic carbon emission
• Secular geological cycles
• Solar activity changes
Glaciers and Disasters - > 70 kinds [3]
Nurek Power Plant 300 m dam. Water reservoir 10 km3 volume. Main supply source [1].
Sarez Lake, Pamir, Tajikistan. Earthquake triggered river dam [4]
Sarez Lake - Google Images
The sequences of sils (mudflows), floods, glacial dams’ breaching [5]
Yak in Pamir is in the Red Book of Natural Heritage [6]
Aral Lake: The Past & Present [7]
httpapparat.ccworldshange-earth
Understanding the glaciers
Three types of glaciers’ regarding the overall motion|rest
1. Fixed (small siting on non steep slopes)
2. Moving down on slope with small speed variations
(Fedchenko etc.)
3. Surging - pulsing (Khirs – Medvejii – Bear, Garmo, Didal
etc.)
The Questions:
Why glaciers can be fixed?
Why glaciers can move (more or less) steadily?
Why glaciers can surge?
Fedchenko’s Glacier, Pamir – A Mountain Valley Glacier [1]
Fedchenko’s Glacier - The facts [1,2,8-13].
• Fedchenko’s glacier is a mountain-valley glacier, one of the biggest in the
Central Asia [1]:
• Location in Pamirs, Tajikistan
• Square - 600 km2,
• Volume - 130 km3,
• Thickness - up to 1 кm,
• Average thickness - 600 m [1],
• Ice density average - 900 kg/m3,
• Mean inclination - 0.06 (4,5 km height per 70 km).
• Mean flow speed - 0,7 m per day
• Mead cover ‘s speed - 0,9 m per days, outer thin one - 0,27 m per day [1]
• In ablation zone - «warm ice» and water accumulation [8]
• Ice - durability limit (slow quazy static pressure) - 4,5-5,0 МPа (45-50 ton/m2)
• Ice creep limit - 55-65% from the durability pressure limit - 2,5-3,0 МPа (see
in [8])
• Glacier ice density - 850-950 кg/m3
• Viscosity coefficient – 1013 Pa·s
Glacier – How it does rest, how it does move?
«Ice movement at depth was long the subject of
debate. Extrusion flow – the hypothesis that
glaciers flow more rapidly at depth than at the
surface – had its proponents, even in the 1930s.
In the early 1900s, Blümcke and Hess used a
thermal drill in a glacier in the Tyrol and attained
bedrock in eleven holes, one of them more than
200m deep. Rods left in the holes gradually tilted
downhill, suggesting that ice moves more rapidly
at the surface than at depth.»
Cuffey K.M., Patterson W.S.B. Physics of glaciers. Elsevier, 2010, 705 pp. [8]
Schematic view of velocity vectors in a mountain glacier [8]
Three Physical States of Ice [8-13]
Physical conditions
Critical ice
thicknesses
Compression lesser than
plasticity limit
0 m <H<250 m
Rest under
small enough
slope
inclinations
Elastic, Rigid
250 m <H<500
m
Viscoplatic
flow
Viscoplastic
0 Pa<р<2.5 x 106 Pa
Compression larger than
limit of plasticity, but
higher than limit of
durability
Physical states
2.5 x 106 Pa<p<4.8 x 106
Pa
Compression higher
than limit of durability
4.8 x 106 Pa <p
500 m <H
Motion of
Agglomerates
block fractures
A Glacier Movement Ideal Scheme
z
Ffriction
He
H
0
P
F
α
Glacier layers cross cut velocity distribution [14]
𝜌 ∙ 𝑔 ∙ sin 𝛼
𝜌𝑒 𝐻𝑒
𝑣=
∙ 𝑧 ∙ 2𝐻 1 + ∙
−𝑧 ,
2𝜇
𝜌 𝐻
𝑔 - the gravity acceleration constant, 𝜌 - the density and 𝜇 viscosity coefficient of the
viscoplastic medium, 𝜌𝑒 - the “floating” slab’s density, 𝐻 - the viscoplastic layer’s thickness
and 𝐻𝑒 - the “floating” slab’s thickness.
“Floating” plate
z
Parabolic dependence of v(z)
Medvejii|Bear Glacier, Pamirs - A Surging Glacier 27.06.2001 [1,2]
Bear GlacIer
A b d u k a h o r River
THE GLACIER ICY 150 m RIVER
http://www.rozov.ru/section28/ [15]
Medvejii - Bear Glacier, Pamirs –
A Surging Glacier
15.8 km long
up to 150 m thick
25.3 km2 square
1m/day regular speed
100 m/day in surging phase
Surging periodicities – 10-12 years
At surging passing down on 2 km,
breaching Abdukakhor river,
17-20 m3 lake rise and
catastrophic threats of inudation,
floods, sils (mudflows), landslides in
Vanch river valley.
Surging Glaciers in Tajikistan
More than 20 surging large glaciers in Tajikistan [1].
THE REGULARITIES:
Ice and snow mass accumulation in the middle or upper part of the glacier, quick
shift down the slope, slowing down while slide body spreading on area.
The ice and snow accumulation of Medvejii/Khirs and bulging reaches 50-70 m high.
Understanding the glaciers: The answers
Why glaciers can be fixed? – Because of the volumes are low and
bodies are in hard, elastic physical state. Gravity force is low.
Why glaciers can move steadily? – Because of the volumes are
enough large and the under layers are in viscoplastic state.
Bedrock shapes are enough steep and gravity force is enough to
drive the glaciers.
Why glaciers can surge? – Because of the bedrock profiles have
cavities and uneven places, providing accumulation of ice and
snow up to the critical values and surging.
Scientific Problems
Whether the glacier layers’ velocity parabolic stratification is true?
What are the real boundary conditions on the glaciers’ bottom bedrock
surface?
Whether the Glen’s law [16] is true and glaciers are really behaving like
Newtonian viscous body?
What is the proper way towards reconstructions of the global climatic
changes and future forecasts?
How the glaciers’ movement is responding to the global climatic
changes?
Fundamental question: how stabilize and protect glaciers?
Glaciers’ Monitoring System in Tajikistan
• TajikHydrometeo at the Gvt. RT.
• Committee on Landuse and Mapping at the Gvt. RT.
• Institute of water resources and ecology - Academy of Sciences of
the Republic of Tajikistan.
• Institute of Geology, Earthquake Engineering and Seismology Academy of Sciences of the Republic of Tajikistan.
• Geology Department - Tadjik National University.
• Physics Department - Tadjik National University.
• International joint projects and cooperation.
http://www.nelt.info/radio02.htm [17]
Automatic radio locator system for the monitoring of Medvejii/Khirs glacier
(the subject to update):
Tajik Technical University. Tel. (992 37) 221-28-44, Fax: 221-28-47 nelt@nelt.info,
nmt@at-communication.com
Conclusions
1. The real time monitoring of the large glaciers is very
important for studies of glaciers;
2. The remote sensing monitoring of glaciers is effective tool
for the prediction and forecasting the related disasters;
3. The qualitative physical modelling of glaciers’ movement
promotes adequate understanding and choosing of
proper measures towards the forecasts of the sequences;
4. International cooperation promotes data acquisition,
analyses, interpretation and taking due measures on
global climate changes challenges.
References
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
Tajikistan: the nature and natural resources. Dushanbe: Donish, 1982, 602 pp. (Russ.).
Glaciers of Tajikistan in global climatic changes. Dushanbe, 2008 116 p. (Russ.).
COES RT - Archive.
Maskaev S. COES RT – Archive.
Karimov F.H. Viscous plastic model for the glaciers flow (Fedchenko’s glacier as an example).
International conference proceedings “Climate changes and natural hazards in mountain areas”,
Dushanbe, 19-21 September 2011, p.115.
Aknazarov O. Private communication.
httpapparat.ccworldshange-earth.
Cuffey K.M., Patterson W.S.B. Physics of glaciers. Elsevier, 2010, 705 pp.
Hook R. LeB. Principles of glacier mechanics. Cambridge Univ. Press, 2005, 429 pp.
Bennett M.R., Glasser N.F. Glacial geology. Chichester, West Sussex: Willey-Blackwell, UK, 2009, 385 pp.
Geological reference book. Ed. K.N. Pfaffenholz. Moscow: Nedra, v.1, 488 pp. (Russ.).
Physical properties of rocks and mineral resources. Chief ed. V.V. Fedynskii. Moscow: Nedra, 527 pp.,
(Russ.).
Vyalov S.S. Ice soil rheology. M.: Strojizdat, 2000, 464 pp. (Russ.).
Karimov F.H. Basic Features of the Landslides’ Viscous Flow. Engineering Geology for Society and
Territory, Volume 2. Landslide Processes. Eds. G. Lollino et all. Springer International Publishing,
Switzerland, 2014, р.1075-1078.
http://www.rozov.ru/section28/
Glen J.W. The creep of polycrystalline ice. Proceedings of the Royal Society, London, A228 (1175), 1955, p.
519–538.
http://www.nelt.info/radio02.htm
Greetings and Thanks for the attention