 | Term | Definition |
| |
earthquake |
the shaking and trembling that results from sudden movement of part of the earth's crust |
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tsunami |
an earthquake on the ocean floor that produces big waves |
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focus |
the point beneath the earth's surface where the rocks break and move, the underground point of origin |
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epicenter |
the point directly above the focus |
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seismic waves |
earthquake waves |
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Primary waves |
1st wave, P, travels the fastest, back-and-forth waves, move through solids, liquids, and gases |
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S waves |
2nd wave, side-to-side, moves through solids, secondary |
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L waves |
surface waves, slowest wave, rise-and-fall circular motion, 3rd, doesn't move through anything |
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seismograph |
instrument that detects and measures seismic waves |
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seismologist |
scientist who studies earthquakes |
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seismogram |
the seismograph's record of waves |
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Richter Scale |
the height of the tallest wavy lines on a seismograph is used to calculate the strenght of a earthquake on this |
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magma |
motlen rock below earth's surface |
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lava |
when magma reaches earth's surface |
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volcano |
the place in the earth's surface where magma and other materials reach earth's surface |
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vent |
the opening from which lava erupts |
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volcanic dust |
the smallest rock particles that are as tiny as grains of flour, less than .25 mm in diameter |
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volcanic ash |
rock particles more than .25 mm in diameter, but less than 5 mm, they are the size of rice grains |
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volcanic bombs |
larger rock particles |
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cinders |
small volcanic bombs the size of golf balls |
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Cinder Cones |
volcanoes made mostly of cinders and other rock particles that have been blown into the air-Mt.Paricutin |
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Shield volcanoes |
volcanoes composed of quiet lava flows-Mauna Loa |
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Composite Volcano |
volcanoes built up of alternating layers of rock particles and lava-Mt. Vesuvius |
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crater |
a funnel shaped pit or depression at the top of a volcanic cone |
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caldera |
if a crater becomes very large as a result of a collaps of its walls it becomes this |
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Most major earthquakes occur in how many zones of the world |
3 |
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Ring of Fire |
the zone that circles the Pacific ocean |
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Mediterranean zone |
zone that is near the Mediterranean Sea |
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Mid-Atlantic Ridge |
zone that goes through the middle of the atlantic ocean |
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the number of earthquakes that cause severe changes in the earth's surface in a year |
20 |
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Faulting |
the most common cause of earthquakes |
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San Andreas |
the name of the major fault line located in California |
