Earthquake Vocabulary

   Crust - the top layer of the earth, which consists of solid rock. Both the continental crust (land
   masses) and oceanic crust (the land beneath the ocean) belong to the crust.

   Epicenter - the point directly above the focus or source of the earthquake.

   Fault - a break or separation in rock, usually between two or more tectonic plates.

   Focus - the source of the earthquake inside the earth, where the rock first begins to break.

   Intensity- the amount of shaking and type of damage at a particular location. Intensity can be
   greater or weaker depending on the distance from the epicenter.

   Liquefaction - this happens when loose, moist soil or sand is shaken so hard that individual grains separate, turning the earth into a soft, fluid slurry that can swallow entire buildings.

   Lithosphere - the uppermost layer of the earth, which consists of all solid rock. It includes both the
   crust and the upper mantle.

   Magnitude - the amount of energy released from the earthquake. The size of the seismic waves at
   the epicenter, which can be determined by the size of the wavy lines on the seismogram.

   Mantle - the layer beneath the crust. The upper mantle is solid rock; the lower mantle is molten

   Mercalli Scale - a subjective measure of the strength of an earthquake. It measures the degree of

   Richter Scale - an objective measure of the strength of an earthquake. It measures the degree of

   Seismic Waves - vibrations that move through the earth in a way similar to waves moving in water.
   They can travel through solids and liquids.

   Seismogram - written recording of the earth's vibrations, produced by a seismograph.

   Seismograph - instrument that plots the intensity of earthquake waves on a roll of specially marked
   graph paper.

   Seismologist - scientist who studies earthquakes.

   Tectonic Plates - individual sections of the lithosphere of the earth. They fit together in a way
   similar to a jigsaw puzzle, but are always moving very slowly, floating on the molten rock of the
   lower mantle.