continental rifting A divergent plate boundary that forms in the middle of a continent.
convergent plate boundary A location where two lithospheric plates come together.
divergent plate boundary A location where two lithospheric plates spread apart.
epicenter The point on the Earth’s surface directly above an earthquake’s focus, which is
the place where the ground breaks.
fault A fracture along which there has been movement of rock on one or both sides.
intraplate activity Geologic activity such as volcanic eruptions and earthquakes that
takes place away from plate boundaries.
island arc A line of volcanoes sitting on an oceanic plate above a subducting oceanic plate
near a deep sea trench.
plate A slab of the earth’s lithosphere that can move around on the planet’s surface.
plate boundary A location where two plates come together.
plate tectonics The theory that the Earth’s surface is divided into lithospheric plates that
move on the planet’s surface.
The driving force behind plate tectonics is mantle convection.
pluton A relatively small body of igneous intrusive rock.
subduction The sinking of one lithospheric plate beneath another.
subduction zone The area where two lithospheric plates come together and one sinks
beneath the other.
supercontinent cycle The cycle in which the continents join into one supercontinent on
one side of the planet and then break apart.
transform fault An earthquake fault where relative motion is sliding past.
transform plate boundary The type of plate boundary where two plates slide past one
another.