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        | The shaking and trembling that results from the movement of rock beneath the earth |  | 
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        | The area beneath the Earth |  | 
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        | The point on the surface directly above the focus. |  | 
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 | Definition 
 
        | waves that compress and expand the ground like an accordion. |  | 
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 | Definition 
 
        | Waves that move more slowly but can produce severe ground movement. |  | 
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 | Definition 
 
        | An instrument that records and measures seismic waves. |  | 
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 | Definition 
 
        | the maximum displacement of the particle motions, or the height of the ripple crest. This is the size of the wiggles on an earthquake recording. From rest to crest. |  | 
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 | Definition 
 
        | the number of times something happens in a certain period of time, such as the ground shaking up and down or back and forth during an earthquake. |  | 
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        | the amount of distance traveled in a specific time frame. |  | 
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        | the distance between successive points of equal amplitude and phase on a wave. |  | 
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        | A weak spot in the crust where molten material or magma comes to the surface. |  | 
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 | Definition 
 
        | A molten mixture of rock-forming substances, gases and water from the mantle. |  | 
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        | a volcanic belt formed by the many volcanoes that rim the Pacific Ocean. |  | 
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 | Definition 
 
        | a pocket of magma beneath the surface. |  | 
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        | A long tube in the ground that connects the magma chamber to the earth |  | 
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 | Definition 
 
        | An opening where molten rock and gas leave the volcano. |  | 
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 | Definition 
 
        | a bowl shaped area that may form at the top of a volcano around the central vent. |  | 
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 | Definition 
 
        | occurs when an explosive eruption hurls out a mixture of hot gases, ash, cinders, and bombs. |  | 
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        | Volcanoes that Scientists expect to awaken in the future and become active. |  | 
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        | Volcano erupting or showing signs that it may erupt in the near future. |  | 
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