runny basaltic lava flows quickly and cools slowly so spreads out over a large area
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2
give an example of a shield volcano
mauna loa
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3
how are composite volcanoes formed
alternating eruptions of fragmented material and lava build up to form a tall volcano.
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4
how are special characteristics of composite volcanoes formed (2)
explosive eruptions can blow the top off the cone leaving a crater with a secondary cone inside, parasitic cones form due to secondary eruptions along the volcano
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5
give an example of a composite volcano
mount etna
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6
how are cinder volcanoes formed
solid material builds up in a steep conical hill around a vent. they are usually not tall
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7
give an example of a cinder volcano
inferno cone in the us
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8
silica causes lava to be more viscous. what is the main source of silica
ocean sediments
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9
what is the result of viscous vs runny lava
viscous lava produces more violent eruptions than runny lava
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10
what are the impacts of pyroclastic flows (3)
health hazard due to toxic components, damage to infrastructure as ash is heavy, damage to ecosystems
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11
what is a lahar
a mixture of ash and rain that flows in a dense, sticky mass
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12
what are the impacts of lahars (3)
can coat land making it unusable, trap people, damage infrastructure
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13
what is the difference between lahars and debris avalanches
\ debris avalanches contain debris and large material whilst lahars are made of finer ash
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14
What is a pyroclastic flow
a hot mixture of gas, ash, and debris blown at high speeds
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15
why does silica thicken lava
it reacts with oxygen to form a lattice structure which creates stringy chains
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