Layers of the Earth and Plate Tectonics Vocabulary

These are all of the vocabulary words you will be responsible for to take the upcoming unit test.

Terms in this set (...)

outer core
a layer of liquid metals; mostly iron and nickle
inner core
a ball of hot, solid metals; mostly iron and nickle
the Earth's thickest layer; made of hot molten rock; has plasticity
the Earth's thinnest layer; solid rock; mostly oxygen and silicon
Earth's crust and the very top layer of the mantle together
a layer of hotter, softer rock in the upper/middle mantle
tectonic plates
many large and small slabs of rock that our lithosphere is broken into; they fit together like puzzle pieces
the ability of a "solid" to move like a "liquid"; able to be molded
convection currents
the movement within the mantle; the core heats the mantle making material rise; when it reaches the top it cools down and sinks again
continental drift
Earth's continents were once joined in a single landmass and gradually moved apart
the Earth's once-existent supercontinent which eventually broke apart
mid-ocean ridge
huge underwater mountain ranges marking where the sea floor is spreading apart
energy transfer by the movement of a material
Theory of Plate Tectonics
the Earth's lithosphere is made up of huge plates that move over the surface of the Earth, floating on the asthenosphere; as plates move they affect the other plates nearby
Alfred Wegener
this scientist proposed the Theory of Continental Drift; he was not taken seriously because he could not prove how plates move
Harry Hess
his Theory of Plate Tectonics helped to explain continental drift;
divergent boundary
occurs where tectonic plates move apart
convergent boundary
occurs where tectonic plates push together
transform boundary
occurs where tectonic plates scrape past each other
rift valley
a gap formed between two diverging plates
magnetic reversal
when Earth's magnetic north and south poles switch places
hot spot
an area of volcanic activity that develops above a plume in the mantle
continental crust
a section of the Earth that contains at least one continent; thicker and lighter than oceanic crust
oceanic crust
a section of the Earth that is under the ocean; thinner and more dense and heavy than continental crust
occurs when one tectonic plate sinks beneath another
continental-continental collision
occurs where two plates carrying continental crust push together
oceanic-oceanic subduction
occurs where one plate with oceanic crust sinks under another plate with oceanic crust
oceanic-continental subduction
occurs when ocean crust sinks under continental crust
a break or fracture in the lithosphere
force when an object pushes, pulls, or presses on another object
shaking of the ground caused by sudden movement of large blocks of rock along a fault
seismic wave
vibrations caused by earthquakes
the point underground where rocks first begin to move during an earthquake
the point on the surface right above the focus
an instrument that continuously records ground movements
Richter Scale
assigns a magnitude number to quantify the energy released by an earthquake
Moment Magnitude Scale
used by seismologists to compare the size of earthquakes; the Richter scale is not as accurate
a smaller earthquake following a more powerful one
when shaking causes soil to act like a liquid
a water wave triggered by an earthquake, volcanic eruption, or landslide
folded mountain
a mountain that forms as continental crust crumples and bends into folds
fault-block mountain
a mountain that forms because blocks of rock move up or down along normal faults
an opening in Earth's crust through which molten rock, rock fragments, and hot gases erupt
molten rock that reaches Earth's surface
pyroclastic flow
a dense cloud of very hot gases and rock fragments that move downhill at high speed
molten rock that has not reached Earth's surface, it is still underground