[email protected]/Glaciology/courses/ess431/LECTURES… · Lecture...
Transcript of [email protected]/Glaciology/courses/ess431/LECTURES… · Lecture...
![Page 1: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/1.jpg)
PRINCIPLES OF GLACIOLOGYESS 431
OCTOBER 19, 2006
Ed Waddington715 ATG [email protected]
GLACIER FLOW
![Page 2: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/2.jpg)
Homework for Thursday Oct 26
See web page – Harry and Gwennestimate the speed of a glacier.
![Page 3: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/3.jpg)
SourcesPaterson, W.S.B. 1994. The Physics of Glaciers. 3rd ed.Pergamon.
Lecture notes from C.F. Raymond
International Glaciological Society Annals of Glaciology 20
I. Joughin and S. Tulazyk, 2002. Science 295, 476
![Page 4: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/4.jpg)
Glacier video
Historic glacier footage shot by UW researchers at Blue Glacier (Mt Olympus) and at Nisqually Glacier (Mt Rainier).
Original movie film has been transferred to digital form.
![Page 5: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/5.jpg)
Essentials of a Glacier
![Page 6: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/6.jpg)
Glacier “Flow” Chart
Here is where we are today
![Page 7: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/7.jpg)
Important Questions
![Page 8: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/8.jpg)
What determines glacier mass balance?
![Page 9: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/9.jpg)
Net Mass balance and
Altitude
![Page 10: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/10.jpg)
Net Mass balance for 13
glaciers
![Page 11: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/11.jpg)
Measuring the Motion of a Glacier
![Page 12: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/12.jpg)
Traditional Surveys
Angles and distances with theodolite and EDM (“total station”)measure locations of markers on/in the ice
Initiallocations
FinallocationsIce
flow
![Page 13: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/13.jpg)
Flow variation across a glacier
![Page 14: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/14.jpg)
Borehole Tilting
![Page 15: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/15.jpg)
Flow variation with depth
Borehole tilting
![Page 16: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/16.jpg)
Crevasse Formation
Like silly putty, ice breaks at right angles to the direction of greatest stretching
So where does the crevasse form in this situation?
![Page 17: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/17.jpg)
inSAR
Interferometric Synthetic Aperture Radar
Rutford Ice Stream, West Antarctica
![Page 18: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/18.jpg)
inSAR Velocities, Ross Ice Streams
Joughin and Tulaczyk. 2002. Science 295, 476.
![Page 19: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/19.jpg)
What Determines Glacier Motion?
ICE DEFORMATION
Ice “flow law”•temperature•fabric, grain size•chemistry, impurities
MOTION OVER BED
Sliding• ?Bed deformation• ?
AVALANCHING
![Page 20: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/20.jpg)
Transport Processes
![Page 21: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/21.jpg)
How is Silly Putty Relevant?
•Viscous flow•Elastic response•Brittle behavior
•Start silly-putty “ice cap”
![Page 22: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/22.jpg)
Idealized Flow Patterns in a valley glacier
![Page 23: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/23.jpg)
Longitudinal Flow Patterns in a Valley Glacier
![Page 24: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/24.jpg)
What determines Ice Transport?
![Page 25: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/25.jpg)
Equilibrium Length of a
Glacier
![Page 26: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/26.jpg)
Forces
•Forces exist inside continuous bodies, (e.g. a glacier)
•These forces can cause the material to deform
•Understanding how this works is our next goal
![Page 27: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/27.jpg)
Are you stressed? Let’s Define Stress
![Page 28: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/28.jpg)
Types of Stress
![Page 29: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/29.jpg)
Magnitudes of Stress
![Page 30: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/30.jpg)
Force of Gravity on a Water Bottle?
Bottle is in free fall …
Volume ~ 1 liter, what is its Mass?
Gravitational acceleration g = 9.8 m s-1
(for purposes of quick-and-dirty estimations, g = 10 m s-1)
![Page 31: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/31.jpg)
Stretching a Rubber Band
![Page 32: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/32.jpg)
Stress in a Rubber Band
Area
![Page 33: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/33.jpg)
Pressure in a Glacier
![Page 34: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/34.jpg)
Depth for 1 Atmosphere Pressure
![Page 35: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/35.jpg)
Shear Stress in a Glacier
![Page 36: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/36.jpg)
Shear Stress τ
![Page 37: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/37.jpg)
How is Shear Stress related to Depth?
![Page 38: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/38.jpg)
An Example of Shear Stress in a Glacier
![Page 39: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/39.jpg)
Are Glacier Thickness and Slope Related?
Suppose a glacier has become steeper or thicker (due to mass imbalance) •It flows faster•It quickly reduces thickness h or slope θ, until τ ~ 1 bar again
Can we estimate glacier thickness from its (known) slope?
![Page 40: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/40.jpg)
Are Glacier Thickness and Slope Related?
Can we estimate glacier thickness from its (known) slope?
h ~ τb/[ρg sinθ] τb~ 105 Pa
![Page 41: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/41.jpg)
Strain Rate ε.
Units are time-1
![Page 42: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/42.jpg)
Strain Rate ε another view
.
![Page 43: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/43.jpg)
Constitutive Relations
Different materials respond differently to applied forces and stresses.
A constitutive relation is a relationship between stress and strain rate for a given material.
Let’s look at some different responses to stress, using silly putty
![Page 44: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/44.jpg)
Constitutive Behavior for Ice
Note that A here is not an Area. A is a constitutive parameter describing the softness of ice.
![Page 45: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/45.jpg)
Comparison – a viscous Fluid
![Page 46: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/46.jpg)
Velocity Profile in a Temperate Glacier
A is constitutive parameter, not Area.
![Page 47: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/47.jpg)
Ice Flux in a Temperate Glacier
Flux Q is total discharge rate across the channel in volume/time (m3 a-1)•We need to average velocity over both depth and width
Areadzdyzyxuxuyxh xW
o/),,()(
),(
0
)(
∫ ∫=
AreaxuxQ ×= )()(
![Page 48: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/48.jpg)
Ice Flux in a wide glacier
When the depth and velocity do not vary much laterally (e.g. on a very wide glacier, or on a big ice sheet) we may sometime talk about ice flux q(x) per unit width of channel. (units of m2 a-1)
)()()( xhxuxq ×=
![Page 49: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/49.jpg)
Velocity Profiles in a Glacier: n=3 or n=1?
n=1 viscousfluid
n=3 Glen Lawfor ice
![Page 50: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/50.jpg)
How can a Crystalline Solid Flow?
![Page 51: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/51.jpg)
Dislocations Help Deformation
![Page 52: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/52.jpg)
Measuring Constitutive Parameters
In simplest form •apply known stress•measure strain rate
![Page 53: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/53.jpg)
Creep Behavior of Ice
![Page 54: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/54.jpg)
Primary CreepSome crystals are “Hard” and others are “Soft” due to the orientation of their basal planes relative to the applied stress•Soft grains deform easily at first•After some deformation has occurred, hard grains start to block deformation of soft grains
Ice gets harder with time
![Page 55: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/55.jpg)
Secondary-Tertiary Creep
•Hard crystals get bent elastically, acquiring strain energy like a stretched spring•This is an energetically unfavorable state•They lose mass to neighbors that are able to creep without picking up strain energy
As hard grains shrink and disappear, ice becomes softer again
![Page 56: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/56.jpg)
Temperature Dependence of Ice Flow
Q = 60 kJ mol-1 activation energy for creepR = 8.314 J mol-1 K-1 gas constantT temperature (Kelvin)
Deformation Rate is proportional to exp(-Q/RT)
![Page 57: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/57.jpg)
Summary: Stress and Strain Rate
Rate
![Page 58: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/58.jpg)
Summary: Mechanical Behavior
![Page 59: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/59.jpg)
Summary: Glacier Motion
![Page 60: edw@ess.washingtonearthweb.ess.washington.edu/Glaciology/courses/ess431/LECTURES… · Lecture notes from C.F. Raymond International Glaciological Society Annals of Glaciology 20](https://reader033.fdocuments.in/reader033/viewer/2022042202/5ea21b8475aa9070a56037b4/html5/thumbnails/60.jpg)
Some Typical Speeds