Our Changing Earth Unit Vocabulary

Front 1

earthquake

Back 1

the shaking that results from the movement of rock beneath Earth's surface

Front 2

epicenter

Back 2

the point on Earth's surface directly above an earthquake's focus

Front 3

fault

Back 3

a break in Earth's crust along which rocks move

Front 4

focus

Back 4

the point beneath Earth's surface where rock first breaks under stress and causes an earthquake

Front 5

magnitude

Back 5

the measurement of an earthquake's strength based on seismic waves and movement along faults

Front 6

plate

Back 6

a section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust

Front 7

plate tectonics

Back 7

the theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle

Front 8

p-wave

Back 8

a type of seismic wave that compresses and expands the ground

Front 9

seismogram

Back 9

the record of an earthquake's seismic waves produced by a seismograph

Front 10

seismograph

Back 10

a device that records ground movements caused by seismic waves as they move through Earth

Front 11

surface wave

Back 11

a type of seismic wave that forms when P-waves and S-waves reach Earth's surface

Front 12

s-wave

Back 12

a type of seismic wave in which the shaking is perpendicular to the direction of the wave

Front 13

transform boundary

Back 13

a plate boundary where two plates move past each other in opposite directions