UNIT 2 INSIDE THE EARTH VOCABULARY LIST
recycling - the process of recovering valuable or useful materials from waste or scrap; the process of reusing some items
petroleum - a liquid mixture of complex hydrocarbon compounds; used widely as a fuel source
natural gas - a mixture of gaseous hydrocarbons, located under the surface of the Earth, often near petroleum deposits,
used as fuel
nuclear energy - the energy released by a fission or fusion reaction; the binding energy of the atomic nucleus
fission - process in which the nuclei of radioactive atoms are split into two or more smaller nuclei
fusion - process in which the two or more nuclei are joined to form a larger nucleus
chemical energy - the energy released when a chemical compound reacts to produce new compounds (hydrogen fuel
cell)
solar energy - the energy received by the Earth from the sun in the form of radiation
wind power - the use of a windmill to drive an electric generator
hydroelectric energy - electrical energy produced by falling water
biomass - organic matter that can be source of energy
gasohol - a mixture of gasoline and alcohol that is used as a fuel
geothermal energy - the energy produced by heat within the Earth
uniformitarianism - a principle that states that geologic processes that occurred in the past can be explained by current
geologic processes
catastrophism - a principle that states that geologic change occurs suddenly
paleontology - the scientific study of fossils
relative dating - any method of determining whether an event or object is older or younger than other events or objects
superposition - a principle that states that younger rocks lie above older rocks if the layers have not been disturbed
geologic column - an arrangement of rock layers in which the oldest rocks are at the bottom
unconformity - a break in the geologic record created when rock layers are eroded or when sediment is not deposited
for a long period of time
fossil - the remains or physical evidence of an organism preserved by geological processes
trace fossil - a fossilized mark that is formed in soft sediment by the movement of an animal
index fossil - a fossil that is found in the rock layers of only one geologic age and that is used to establish the age of the
rock layers
geologic time scale - the standard method used to divide the Earth's long natural history into manageable parts
extinction - the death of every member of a species
crust - the thin and solid outermost layer of the Earth above the mantle
mantle - the layer of rock between the Earth's crust and core
core - the central part of the Earth below the mantle
lithosphere - the solid, outer layer of the Earth that consists of the crust and the rigid upper part of the mantle
asthenosphere - the soft layer of the mantle on which the tectonic plates move
mesosphere - the strong, lower part of the mantle between the asthenosphere and the outer core
tectonic plate - a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle
Continental Drift Theory - the hypothesis that states that the continents once formed a single landmass, broke up and
drifted to their present locations
Seafloor Spreading Theory - the process by which new oceanic lithosphere forms as magma rises toward the surface
and solidifies
Plate Tectonics Theory-the theory that explain how large pieces of the Earth's outermost layer, called tectonic plates,
move and change shape
convergent boundary-the boundary formed by the collision of two lithospheric plates
divergent boundary-the boundary between two tectonic plates that are moving away from each other
transform boundary-the boundary between tectonic plates that are sliding past each other horizontally
compression - stress that occurs when forces act to squeeze an object
tension-stress that occurs when forces act to stretch an object
folding - the bending of rock layers due to stress
fault - a break in a body of rock along which one block slides relative to another
uplift - the rising of regions of the Earth's crust to higher elevations
subsidence - the sinking of regions of the Earth's crust to lower elevations
earthquake - the quick and sudden movement of the earth caused when rock breaks
seismology-the study of earthquakes
deformation-the bending, tilting, and breaking of the Earth's crust; the change in the shape of rock in response to stress
elastic rebound-the sudden return of elastically, deformed rock to its undeformed shape
seismic wave - a wave of energy that travels through the Earth, away from an earthquake in all directions
P-wave- a seismic wave that causes particles of rock to move in a back-and-forth direction
S-wave - a seismic wave that causes particles of rock to move in a side-to-side direction
Surface wave - a seismic wave that moves along the Earth's surface and produce motion mostly in the upper few
kilometers of the crust - most destructive
seismograph-an instrument that records vibrations in the ground and determines the location and strength of an
earthquake
seismogram - a tracing of earthquake motion that is created by a seismograph
epicenter - the point on Earth's surface directly above an earthquake's starting point, or focus
focus - the point along a fault at which the first motion of an earthquake occurs
Richter Magnitude Scale - a scale used to measure the strength of an earthquake - 1 - 10
Modified Mercalli Intensity Scale - a scale used to measure the intensity of an earthquake I - XII
gap hypothesis - a hypothesis that is based on the idea that a major earthquake is more likely to occur along the part of
an active fault where no earthquakes have occurred for a certain period of time
seismic gap - an area along a fault where relatively few earthquakes have occurred recently but where strong
earthquakes have occurred in the past
volcano- a vent or fissure in the Earth's surface through which magma and gases are expelled
magma chamber - the body of molten rock that feeds a volcano
vent - an opening at the surface of the Earth through which volcanic material passes
shield volcano - built of layers of lava released from repeated nonexplosive eruptions
cinder cone volcano - made of pyroclastic material usually produced from moderately explosive eruptions
composite volcano- most common type of volcano, form from explosive eruptions of pyroclastic material and quieter
flows of lava
crater - a funnel-shaped pit near the top of the central vent of a volcano
caldera - a large, semicircular depression that forms when the magma chamber below a volcano partially empties and
causes the ground above to sink
lava plateau - a wide, flat landform that results from repeated nonexplosive eruptions of lava that spread over a large
area
subduction zone- a convergent boundary where one plate moves under the other plate, often causing volcanic
activity
rift zone - an area of deep crack that forms between two tectonic plates that are pulling away from each other
(divergent boundary)
hot spots - a volcanically active area of the Earth's surface far from a tectonic plate boundary