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a force that acts on rock to change its shape or volume


stress that stretches rock so that it becomes thinner in the middle


squeezes rock until it folds or breaks


stress that pushes masses of rock in opposite directions, in a sideways movement

normal fault

a type of fault where the hanging wall slides downward; caused by tension in the crust

hanging wall

the block of rock that forms the upper half of a fault


The block of rock that forms the lower half of a fault.

reverse fault

a type of fault where the hanging wall slides upward; caused by compression in the crust

strike-slip fault

A type of fault in which ricks on either side move past each other sideways with little up or down motion.


an upward fold in rock formed by compression of Earth's crust


a downward fold in rock formed by compression in earth's crust


a large area of flat land elevated high above sea level


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


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


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

P wave

A type of seismic wave that compresses and expands the ground.

surface wave

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

Mercalli scale

a scale that rates earthquakes according to their intensity and how much damage they cause at a particular place


The measurement of an Earthquake's strength based on seismic waves and movement along faults

Richter scale

a scale that rates an earthquake's magnitude based on the size of its seismic waves


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

moment magnitude scale

a scale that rates earthquakes by estimating the total energy released by an earthquake


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


the force that opposes the motion of one surface as it moves across another surface


The process by which an earthquake's violent movement suddenly turns loose soil into liquid mud


an earthquake that occurs after a larger earthquake in the same area


a large wave produced by an earthquake on the ocean floor

base-isolated buidling

A building mounted on bearings designed to absorb the energy of an earthquake

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