Description:
Land subsidence and related earth fissures have become widespread occurrences in southern Arizona. As
the areal and vertical extent of subsidence has increased, more earth fissures have been discovered. As a
result, there is growing concern about existing and potential damage caused by these phenomena. This
concern is reflected by the increasing number of requests for information received by the Arizona
Geological Survey (AZGS), which has prompted the compilation of this bibliography, establishment of a
Steering Committee on Subsidence and Earth Fissures, and formation of the Center for Land-Subsidence
and Earth-Fissure Information (CLASEFI), which is supported jointly by the AZGS and the Arizona
Department of Water Resources.
Although many human-induced and natural processes give rise to land subsidence and earth fissures, those
in southern Arizona are closely linked to long-term extraction of ground water by man. This bibliography,
therefore, focuses on subsidence resulting from ground-water withdrawal. As ground water is removed
from some alluvial aquifers, sediment particles in those aquifers lose some of their ability to support the
overburden, the grains become more closely packed, and aquifer volume decreases. The land surface sinks
(subsides) in response to the decreased aquifer volume at depth. This type of subsidence proceeds
gradually, but, with time, can spread over large areas and cause significant deformation.
( 21 pages)