Glacial Bottom Processes
Most of the important processes controlling glacial motion occur in the ice-bed contact—even though it is only a few meters thick. Glaciers will move by sliding when the basal shear stress drops below the shear resulting from the glacier's weight.
- τD = ρgh sin α
- where τD is the driving stress, and α the ice surface slope in radians.
- τB is the basal shear stress, a function of bed temperature and softness.
- τF, the shear stress, is the lower of τB and τD. It controls the rate of plastic flow, as per the figure (inset, right).
For a given glacier, the two variables are τD, which varies with h, the depth of the glacier, and τB, the basal shear stress.
Read more about this topic: Ice Sheet Dynamics
Famous quotes containing the words bottom and/or processes:
“The distinction between children and adults, while probably useful for some purposes, is at bottom a specious one, I feel. There are only individual egos, crazy for love.”
—Don Barthelme (1931–1989)
“It has become a people’s war, and peoples of all sorts and races, of every degree of power and variety of fortune, are involved in its sweeping processes of change and settlement.”
—Woodrow Wilson (1856–1924)