Problems of Ground Subsidence

Abstract

usually been academic, principally to further his knowledge of the processes of formation and change of the earth's surface or to furnish an explanation of geologic observations. The failure of roof supports in mining operations conducted relatively close to the surface of the ground is one of the commonest causes of subsidence. There are, of course, many others. The surface effects of various forms of subsidence may be quite marked and often present a serious problem. Small degrees of subsidence have frequently accompanied domestic water pumping, extensive production of ground water for irrigation, and drainage work in some areas. There has been little opportunity to chart subsidences because they are unobservable except through the use of precise surveying methods. In addition, there often are insufficient surface problems to justify engineering study. In most cases, knowledge of the subsidence probably does not exist. In recent years, however, some of the larger subsurface operations have been located beneath extensive population developments, including highvalue surface improvements. With increasing population along the shores of the continental United States and