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19 Cards in this Set
- Front
- Back
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Seismologist? |
This is a person who studies earthquakes. |
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Seismograph? |
This is an instrument that records and measures earthquakes. |
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The focus? |
This is the spot at the origin of an earthquake. |
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The epicentre? |
This is the spot directly above the focus on the earth's surface. |
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Seismic waves? |
These are waves that radiate from the focus and are causes of destruction. |
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Name two types of seismic waves? |
Body waves and surface waves. |
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Explain surface waves. |
These are waves that make the ground move in two ways at a time: (a) in a rolling motion like waves at sea (b) in a snake-like sideways movement. This causes buildings to roll and twist at the same time. |
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Name two types of scales that measures earthquakes. |
Richter scale and Mercalli scale. |
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Explain Richter scale. |
This is a scale that indicates the size or magnitude of an earthquake. |
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Explain Mercalli scale. |
This measures earthquakes damage on a 12-point scale. |
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Explain the different magnitudes on the Richter scale. |
An earthquake measuring 7 on the Richter scale is 10 times more powerful than a 6, and 100 times more than a 5. |
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Volcanoes. |
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Where do volcanoes occur? |
Volcanoes occur at hot spots. |
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What is a hot spot? |
These are areas where large batholiths are near the surface at locations away from plate boundaries. E.g Yellowstone National Park, USA. |
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What are black smokers? |
These are chimney like openings at mid-ocean ridges. |
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5 positive effects of volcanoes? |
1. Lava soils are rich in iron, which is good for coffee production. 2. Geothermal energy can be generated from hot rock and geysers. 3. Mineral ores and veins are important resources. 4. New land is created on volcanic islands. 5. Tourists visit volcanic islands e.g Iceland, Sicily. |
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3 negative effects of volcanoes? |
1. People can be killed from clouds of poisoness gas and ash called nuees ardentes. 2. Lava flows destroy houses and towns. 3. Eruptions force people to evacuate their homes. |
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4 ways to reduce the effects of earthquakes? |
1. Enforce strict building regulations in earthquake-prone regions. 2. Install earthquake-proof technology in new tall buildings. 3. Practise emergency earthquake drills and regional emergency plan procedures. 4. Develop tsunami warning stations for all countries located along the Pacific and Indian Ocean regions. |
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4 ways to predict eruptions and earthquakes? |
1. Scientific instruments are placed in vulnerable regions e.g strain metres, lasers. 2. Seismic gaps is places where an earthquake had not occured for a long time an is surrounded by areas of recent earthquake activity. These are spots where earthquakes are most likely to occur in the future. A dating pattern of past earthquakes and volcanic eruptions help to predict the likelihood of new ones. 3. Animal behaviour help to predict as they are sensitive to tremors. |
