mercalli		Block of rock lying above a fault.
syncline		They carry energy from an earthquake.
tension		A break in the rock of the crust.
momentmagnitude		This scale rates an earthquake by measuring the size of the seismic waves.
liquefaction		Shaking and trembling of the Earth.
stress		A fold in rock that bends downward to form a valley.
aftershock		This scale measures the level of damage caused by an earthquake.
footwall		When an earthquake's violent shaking turns soil into liquid mud.
epicenter		Causes rock to become thinner in the middle.
richter		When rock moves in two different directions causing breakage.
seismicwaves		A force that acts on rock to change its shape or volume.
shearing		Measures and records the vibrations produced by an earthquake.
seismograph		Rock that folds upward into an arch.
fault		To watch closely.
compression		Squeezes rock until it folds or breaks.
focus		Area beneath Earth's surface where rock under stress breaks.
earthquake		An earthquake that occurs after a larger earthquake has taken place.
monitor		This measures the total energy released by an earthquake.
plateau		Point on the surface directly above the focus.
hangingwall		Large flat area of land elevated high above sea level.
anticline		Block of rock lying below a fault.