Environmental Engineering Reference
In-Depth Information
Geologic hazards:
One of several types of adverse geologic conditions capable of
causing damage or loss of property and life. These hazards include ava-
lanches, earthquakes, forest fires, geomagnetic storms, ice jams, landslide,
mudslide, rock falls, torrents, volcanic eruptions, alluvial fans, geyser
deposits, liquefaction, sand dune migration, thermal springs, and stream
erosion.
Geographic information system (GIS):
A computerized system to compile, store,
analyze, and display geographically referenced information.
Geologic sequestration:
A type of engineered sequestration where captured carbon
dioxide is injected for permanent storage into underground geologic reser-
voirs, such as oil and natural gas fields, saline aquifers, or abandoned coal
mines.
Geothermal:
Of or relating to the Earth's interior heat.
Geothermal energy:
The Earth's interior heat made available for use by extracting
it from hot water or rocks. As used at electric power plants, hot water or
steam extracted from geothermal reservoirs in the Earth's crust is supplied
to steam turbines at electric power plants that drive generators to produce
ele ct r icit y.
Geothermal gradient:
The rate of temperature increase in the Earth as a function of
depth. Temperature increases an average of 1°F for every 75 feet in descent.
Geothermal heat pumps:
Devices that take advantage of the relatively constant
temperature of the Earth's interior, using it as a source and sink of heat for
both heating and cooling. For cooling, heat is extracted from the space and
dissipated into the Earth; for heating, heat is extracted from the Earth and
pumped into the space.
Geothermal plant:
A plant in which a turbine is driven either from hot water or by
natural steam that derives its energy from heat found in rocks or fluids at
various depths beneath the surface of the Earth. The fluids are extracted by
drilling or pumping.
Geothermal resources:
The natural heat of the earth that can be used for beneficial
purposes when the heat is collected and transported to the surface.
Geyser:
A spring that shoots jets of hot water and steam into the air.
Gigawatt (GW):
One billion watts or 1000 megawatts.
Gigawatt-electric (GWe):
One billion watts of electric capacity.
Gigawatt-hour (GWh):
One billion watt-hours.
Glazing:
Transparent or translucent material (glass or plastic) used to admit light or
to reduce heat loss; used for building windows, skylights, or greenhouses or
for covering the aperture of a solar collector.
Global positioning system (GPS):
A navigation system using satellite signals to fix
the location of a radio receiver on or above the Earth's surface.
Global warming:
An increase in the near-surface temperature of the Earth. Global
warming has occurred in the distant past as a result of natural influence
(it is a cyclical event that has occurred throughout Earth's history), but the
term is most often used to refer to the warming predicted to occur as a result
of increased emissions of greenhouse gases from commercial or industrial
resources.
