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vibration of earth produced by rapid release of energy


the point in earth where an earthquake starts


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


fractures in earth where movement has occured

Elastic Rebound Hypothesis

explanation for the release of energy stored in deformed rocks


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


a small earthquake that often proceeds a major earthquake


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


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

Surface Wave

seismic wave that moves on earths outer layer

P wave

push and pull waves

S wave

A type of seismic wave that moves the ground up and down or side to side.

Moment Magnitude

A measurement of earthquake strength based on the size of the area of the fault that moves, the average distance that the fault blocks move, and the rigidity of the rocks in the fault zone.


occurs when an earthquake's violent shaking suddenly turns loose soft soil into liquid mud


a giant wave caused by an earthquake on the ocean floor

Seismic Gap

an area along a fault where there has not been any earthquake activity for a long period of time


the outer layer of the Earth


the layer of the earth between the crust and the core


the solid part of the earth consisting of the crust and outer mantle


The lower layer of the crust, weak

Outer Core

The liquid layer of Earth made of nickel and iron.

Inner Core

solid, dense center of the Earth


the boundary between the earth's mantle and crust

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