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3.4 Stress Calculation
A glacier flows in response to stress within the ice mass by the force of gravity.
Stress is a measure of the intensity of push or pull resulting due to the application of
external force and this external force tends to change the motion of a mass from one
state to the other or changes within the state of existence itself. In reality, no glacier
has uniform thickness throughout its body. Therefore, the force due its weight is
applied on a specific orientation. The Traction is the Force per unit area on a surface
of specific orientation.
Stress can act at three directions. If it acts at right angles to a surface, then it is a
normal stress. If it acts parallel to a surface, it is shear stress, whereas if it acts at an
acute angle to the surface, it is simply a surface stress. Therefore the surface stress
represents a pair of equal and opposite tractions acting across a surface at a particular orientation. Normal stress may be compressive or tensile in nature. In both cases,
a pair of tractions act at right angles, but their orientation differs as per their nomenclature. Shear stress represents two tractions acting parallel to the surface.
Therefore, the normal stress at the base of a glacier with minimal slope can be
represented by
σ ρ
= gh
(2)
where, σ = normal stress,
ρ = density of ice mass,
g = acceleration due to gravity,
h = thickness of the glacier.
But where the surface slope is not uniform or it is uneven, then the basal shear
stress is calculated as per the following equation
τ ρ
θ
= ghsin
(3)
where, τ = basal shear stress,
ρ = density of ice mass
g = acceleration due to gravity
h = thickness of the glacier
θ = surface slope
3.5 Crevasse Mapping
Longitudinal stress in the glaciers modifies basal shear stress and is observed in the
form of pushing or pulling effect of the ice mass. Accelerating and decelerating ice
mass imposes tensile and compressional stresses respectively and it is observed in
Glacier Stress Pattern as an Indicator for Climate Change
3.4 Stress Calculation
A glacier flows in response to stress within the ice mass by the force of gravity.
Stress is a measure of the intensity of push or pull resulting due to the application of
external force and this external force tends to change the motion of a mass from one
state to the other or changes within the state of existence itself. In reality, no glacier
has uniform thickness throughout its body. Therefore, the force due its weight is
applied on a specific orientation. The Traction is the Force per unit area on a surface
of specific orientation.
Stress can act at three directions. If it acts at right angles to a surface, then it is a
normal stress. If it acts parallel to a surface, it is shear stress, whereas if it acts at an
acute angle to the surface, it is simply a surface stress. Therefore the surface stress
represents a pair of equal and opposite tractions acting across a surface at a particular orientation. Normal stress may be compressive or tensile in nature. In both cases,
a pair of tractions act at right angles, but their orientation differs as per their nomenclature. Shear stress represents two tractions acting parallel to the surface.
Therefore, the normal stress at the base of a glacier with minimal slope can be
represented by
σ ρ
= gh
(2)
where, σ = normal stress,
ρ = density of ice mass,
g = acceleration due to gravity,
h = thickness of the glacier.
But where the surface slope is not uniform or it is uneven, then the basal shear
stress is calculated as per the following equation
τ ρ
θ
= ghsin
(3)
where, τ = basal shear stress,
ρ = density of ice mass
g = acceleration due to gravity
h = thickness of the glacier
θ = surface slope
3.5 Crevasse Mapping
Longitudinal stress in the glaciers modifies basal shear stress and is observed in the
form of pushing or pulling effect of the ice mass. Accelerating and decelerating ice
mass imposes tensile and compressional stresses respectively and it is observed in
Glacier Stress Pattern as an Indicator for Climate Change