Humans as Geologic Agents
Homo sapiens is the only known species to consciously effect change to the Earth’s geologic environment. We reshape the Earth; intensify erosion; modify rivers; change local climates; pollute water resources, soils, and geologic media; and alter soils and the biosphere. We dig holes in it, remove parts of it, and bury highly toxic materials in it. In this volume, the authors explore human impact on the Earth and attempt to answer the following questions. What have we done to Terra? How fast have we effected change? Are the changes permanent? Are they good, or have we inadvertently caused more damage? Can we, should we, repair some or all of these changes? These are important questions for the geoscience community because, as those most knowledgeable about the Earth and its resources, geologists play a major role in sustaining and preserving the Earth.
Impacts of land subsidence caused by withdrawal of underground fluids in the United States
Published:January 01, 2005
Thomas L. Holzer, Devin L. Galloway, 2005. "Impacts of land subsidence caused by withdrawal of underground fluids in the United States", Humans as Geologic Agents, Judy Ehlen, William C. Haneberg, Robert A. Larson
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Lowering of the land surface of large areas has been a major unintended consequence of groundwater and petroleum withdrawal by humans. Approximately 26,000 km2 of land in the United States has been permanently lowered. The decrease of land-surface elevation, known as land subsidence, typically occurs at rates measured in centimeters per year. However, the irreversible accumulation of its effects clearly qualifies humans as major geologic agents. Subsidence causes permanent inundation of land, aggravates flooding, changes topographic gradients, ruptures the land surface, and reduces the capacity of aquifers to store water. This paper reviews the mechanism, occurrence and history, impacts, and efforts by society to control land subsidence caused by underground fluid withdrawal in the United States.