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26 Cards in this Set
- Front
- Back
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Define earthquake
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A vibration(shaking or movement) of Earth, caused by the release of energy that has been stored
in Earth's rocks along a fault. many happen near the boundaries between tectonic plates |
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Define aftershock.
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A shock that occurs after the principal shock of an earthquake
less powerful, |
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Define Richter scale.
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Describes the magnitude or strength of an earthquake.
**numbers range from 1 to 10. **each increase of 1.0 reprsents an increase of 30 times in the energy released by an earthquake |
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Define Magnitude.
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the amount of energy released by the quake (force and strength)
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Who is a seismologist and what is a seismograph?
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Seismologist is a scientist who studies earthquakes.
A seismograph is the instrument that records the intensity, duration and nature of earthquake waves. |
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Define fault.
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A break in rocks along which the rocks have moved
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Define Focus.
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the point or place at which the earthquake begins
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Define epicenter.
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the point on Earth's surface directly above the focus
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Define P waves.
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waves move out in all directions from the earthquake focus. The primary waves push and pull the rocks causing them to vibrate in the same direction in which the wave is traveling.
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Define S waves.
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S waves move out in all directions from the earthquake focus. The secondary waves cause the rocks to move at right angles to the direction in which the wave is traveling.
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Define L waves.
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When the P and S waves punch into Earth's surface, they cause the formation of L waves or surface waves. L waves move along the surface causing the rocks to move up and down. These are the most destructive earthquake waves.
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Define tsunami.
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A large and powerful ocean wave usually caused by an underwater earthquake.
they can cause great destruction if it strikes on land. |
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Define Volcano.
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any opening in Earth's crust through which hot gases, rocks, and melted material erupt.
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Define magma.
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the ho, molten rock deep inside Earth.
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Define lava.
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Magma that flows out onto Earth's surface from a volcano.
temperature can be higher than 1,100 C (2,012 F) |
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What types of debris can spew from a volcano?
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Bombs: volcanic rocks baseball in size or bigger.
Volcanic dust or ash: .25mm to .5 mm can be carried hundreds or thousands of kilometers from the volcano |
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Name the Classifications of volcanos based on eruptions.
there are four. |
1. Active: one that erupts constantly.
2. Inermitten: erupt on a regular basis. ex: Mt. Vesuvius. 3. Dormant: haven't erupted in awhile but could erupt in the near future. 4. Extinct: have not erupted |
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Name the three classifications of volcanoes based on the way they erupt.
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1. Cinder-cone
2. Shield 3. Composite-cone |
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Explain cinder-cone volcanoes.
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Sticky bits of volcanic material pea size
small and steep-sloped, formed from layers of cinders result from explosive eruptions |
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Explain composite-cone volcano.
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A kind of volcano formed when explosive eruptions of sticky lava alternate with quieter eruptions of volcanic rock bits.
steep slopes near top but gentle slopes closer to base ex: Mt. Vesuvius |
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Explain shield-cone volcano.
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form when lave flows quietly from a crack in Earth's crust.
large mountains that have gentle slopes ex: Mauna Loa (largest volcano on Earth) |
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Define island arcs.
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A chain of volcanoes formed from magma that rises as a result of an oceanic plate sinking into the mantle.
ex: Philippine Islands |
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Define seismometer and tiltmeter.
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Seismometer: an instrument that detects Earth's movements.
Tiltmeter: measures any change in the slope of an area both help to indicate presence of magma and/or gases within the volcano |
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What are hot spots?
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extremely hot places deep within Earth's mantle and contains a chamber of magma
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Define caldera.
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a large circular depression, with a diameter of about 5km lies within the volcano's summit (top of the volcano)
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Define rifting.
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the process by which magma rises to fill the gap between two plates that are moving apart.
may split the continent into two parts ex: Great African Rift Valley |
