Geology Reference
In-Depth Information
Figure 9.8.
Summary of frost heave types and associated velocity-depth profi les of solifl uction
movement. From Matsuoka (2001c). Reprinted from Earth Science Reviews, with permission from
Elsevier.
alpine regions with strong diurnal and seasonal temperature rhythms, frost creep and
needle ice may be the dominant mass-wasting process for much of the year. On the other
hand, observations from high-latitude environments indicate that either frost creep or
gelifl uction may dominate, not only in any given year but also in different sectors of the
same slope depending upon moisture conditions. In areas where the base of the active
layer contains icy lenses, an end-of-summer plug-fl ow movement may dominate.
9.4.2. Frost Creep
Frost creep is associated with either one-sided or two-sided freezing (see Figures 9.9 and
9.10). One-sided frost creep involves movement decreasing from the surface downwards
and depends upon the frequency of freeze-thaw cycles, angle of slope, moisture available
for heave, and frost susceptibility of the soil. Thus, if the slope angle is
σ
, the heave normal
