This book provides a general survey of Geocryology, which is the study of frozen ground called permafrost. Frozen ground is the product of cold climates as well as a variety of environmental factors. Its major characteristic is the accumulation of large quantities of ice which may exceed 90% by volume. Soil water changing to ice results in ground heaving, while thawing of this ice produces ground subsidence often accompanied by soil flowage. Permafrost is very susceptible to changes in weather and climate as well as to changes in the microenvironment. Cold weather produces contraction of...