In geomorphology, creep is a noun in terms of process as well as a verb in terms of velocities. Apart from the creep of glacier ice, two kinds of creep processes are of interest to geographers: (1) the mass-movement downhill creep of rock, sediment, soil, and snow and (2) the aseismic creep, or slow movement along part of a normally earthquake-producing fault or on a volcano. In spite of their differences, both processes involve long-term and almost imperceptible slow movement of rock and earth materials. In terms of velocities of mass movement, creeping motions are described as very slow or extremely slow. Very slow rates of motion are less than 5 × 10–5 mm/s (millimeters per second), with a typical velocity of 1.6 m/yr. (meters ...