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| this lava would be very painful to walk across with bare feet |
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| very fine particles of molten rock that can stay in the upper atmostphere for years |
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| hot liquid that forms when rock melts |
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| even though this is far from any plate boundaries, it is still active |
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| a good name for the Pacific area with more than its share of volcanoes |
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| magma and gases are expelled thru this vent or fissure in the earth's surface |
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| scientists watch this looking for buldges |
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| a hole in the earth's crust |
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| this deep set of cracks forms when techtonic plates pull away from each other |
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| when the magma chamber below a volcano partially empties this large semi-circular depression forms |
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| a good synonym for this volcano might be 'sleeping' |
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| repeated flows of lava will create this wide flat land form |
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| this funnel shaped pit forms around a volcano's central vent |
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| this is where molten rock collects underground |
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- is formed by explosive erruptions that are followed by lava outpourings
- AKA a stratovolcano
- has a broad base and steep sides towards the top
- a combination of explosive and nonexplosive eruptions creates this |
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- errodes very quickly
- is often found in clusters
- consists entirely of pyroclastic material |
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- has sides that slope gently
- is made entirely of runny lava
- forms from repeated nonexplosive erruptions |
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| long cracks in the earth's crust |
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| ocurrs after an explosive eruption |
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| where volcanoes most likely form |
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| you would expect to see this during a nonexplosive eruption |
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| an explosive eruption is more likely |
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| if the water content of magma is high |
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| pyroclatic material gets its name from a word that means 'little stones' |
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| cool stiff lava that forms jumbled heaps of sharp chunks near the vent |
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| lava that flows most like dripping wax |
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| forms when magma explodes into the air and hardens |
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| possible climate change caused by a volcanic eruption |
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Definition
| ash blocks sunlight, causing temperature to drop |
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| three main types of volcanoes |
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Definition
| shield, composite, cinder cone |
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| temperature increases and pressure decreases |
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| when an oceanic plate collides with a continental plate, the oceanic plate is usually subducted because |
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| oceanic crust is denser and thinner than continental crust |
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| the volcanoes of Hawaii and other places far from tectonic plate boundaries |
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| instrument that measures changes in a volcano's slope |
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| what happens to the atmosphere after large-scale volcanic eruptions |
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Definition
| enormous amts of volcanic ash and gases are ejected into the upper atmosphere |
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| as volcanic ash and gases spread throughout the atmosphere they can |
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| block enough sunlight to cause global temperatures to drop |
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| what is one effect of the drop in global temperatures caused by the eruption of Mount Tambora in 1815? |
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| it caused food shortages in N. America and Europe |
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| Volcano eruptions can be X times stronger than the explosion produced by the first atomic bomb |
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| what happens during non-explosive eruptions? |
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| huge amts of lava can be released |
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| most of the sea floor is covered with |
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| lava from nonexplosive eruptions |
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| what would you see during an explosive volcanic eruption |
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Definition
| hot debris, ash and gas shooting into the air |
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| during an explosive eruption, where do larger pieces of debris fall? |
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| how quickly can an explosive eruption demolish a mountainside |
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| what about the magma affects how explosive an eruption will be? |
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| why is magma with high water content more likely to cause an explosive eruption? |
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| the pressure suddenly decreases and the water and other compounds become gases; as the gas expands rapidly an explosion can result. |
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| the solid form of lava that is so frothy with gas when it reaches the surface |
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| 2 reasons that magma with a high silica content tend to cause explosive eruptions |
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- hardens in a volcanoes vent and plugs it up
- prevents water vapor ad other gases from escaping |
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| why is magma with less silica less likely to cause explosive eruptions |
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Definition
| more fluid, runnier consistency and gases can escape more easily |
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| what is the difference b/t the flow of lava with high viscosity and the flow of lava with low viscosity? |
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Definition
| high viscosity stiff and flows slowly, low viscosity more fluidand flows quickly |
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| forms underwater in rounded lumps |
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| large blobs of magma that harden in the air |
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| when large amounts of hot ash, dust and gases are ejected from a volcano the result is dangerous type of volcanic flow; the pyroclastic materials can race downhill at speeds of more than 200 km/hr; temperature at the center of the flow is 700 degree C |
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