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shaking and vibration at the surface of the earth resulting from underground movement along a fault plane of from volcanic activity


(geology) a crack in the earth's crust resulting from the displacement of one side with respect to the other

sesimic waves

energy from inside earth


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


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

primary waves

waves that travel outward from an Earthquake's focus and cause particles in rocks to move back and forth in the same direction the wave is moving

secondary waves

waves that travel outward from an earthquke's focus and move through Earth by causing particles in rocks to vibrate at right angles to the direction of the wave

surface waves

waves of energy that reaches Earth's surface during an earthquake, travel outward from the epicenter, and move rock particles up & down & side to side


a scientist who studies earthquakes


Instrument used to measure horizontal or vertical motion during an earthquake.


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


a fissure in the earth's crust (or in the surface of some other planet) through which molten lava and gases erupt


molten rock in the earth's crust


rock that in its molten form (as magma) issues from volcanos

hot spots

areas of volcanic activities that result from plumes of hot solid material that have risen from deep inside earths mantle

shield volcano

a wide, gently sloping mountain made of layers of lava and formed by quiet eruptions

composite volcano

volcano built by alternating explosive and quiet eruptions that produce layers of tephra and lava; found mostly where Earth's plates come together and one plate sinks below the other

cinder cones

Form when lava is thick and stiff and has a cone-shape.

volcanic ash

sand-sized particles of igneous rock that form when a spray of liquid magma is blown from a volcanic vent by escaping gas


resistance of a liquid to sheer forces (and hence to flow)

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