Geological Activity and Earthquakes

Front

shear stress

Back

stresses that move past each other in opposite directions

Front

tension

Back

stresses that pull material in opposite directions; occurs at or near divergent boundaries

Front

compression

Back

stresses that push toward each other; occurs at or near convergent boundaries

Front

confining stress

Back

stress from the weight of material above the buried object.

Front

deformation

Back

the change of shape that a rock undergoes when it has been altered by stress

Front

earthquake

Back

shaking of the ground due to the release of energy stored in rock

Front

elastic rebound theory

Back

states that stresses build in rocks until they can no longer bend elastically, then break, causing an earthquake

Front

epicenter

Back

Point on Earth's surface directly above an earthquake's focus

Front

focus

Back

Point at the depth where the rocks ruptured to produce earthquakes; place where quake waves originate

Front

gap hypothesis

Back

states that earthquake hazard increases with the amount of time since the last large earthquake