You are asked to interpret some aspects of the flow in and deformation of this glacier. Note that flow is driven by the gravitational gradient displayed as slope of the glacier surface, and that the flow velocity at any point is a complex function of mass balance, cross-sectional area, ice temperature, shape of the channel, and ice surface slope. The line A-A' represents a line of stakes across the glacier and the dashed line represents the same stakes two years later. Calculate the average daily velocity of the glacier surface at that point. In your discussion, consider the variables hidden in that calculation.
Crevasses are open fractures in glacial ice.
Crevassing occurs where stress application locally exceeds the strength of ice, causing fracture. Most crevasses are the result of differential flow velocities, resulting in tension, compression, and shear. Ice is generally incompressible, although flow velocities may change under compression, but fractures under tension and shear. Generally, only tension fractures will open to form crevasses. 6.3, p. 213, in Benn and Evans.