Studied by 16 peoplehow are shield volcanoes formed
runny basaltic lava flows quickly and cools slowly so spreads out over a large area
give an example of a shield volcano
mauna loa
how are composite volcanoes formed
alternating eruptions of fragmented material and lava build up to form a tall volcano.
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
give an example of a composite volcano
mount etna
how are cinder volcanoes formed
solid material builds up in a steep conical hill around a vent. they are usually not tall
give an example of a cinder volcano
inferno cone in the us
silica causes lava to be more viscous. what is the main source of silica
ocean sediments
what is the result of viscous vs runny lava
viscous lava produces more violent eruptions than runny lava
what are the impacts of pyroclastic flows (3)
health hazard due to toxic components, damage to infrastructure as ash is heavy, damage to ecosystems
what is a lahar
a mixture of ash and rain that flows in a dense, sticky mass
what are the impacts of lahars (3)
can coat land making it unusable, trap people, damage infrastructure
what is the difference between lahars and debris avalanches
debris avalanches contain debris and large material whilst lahars are made of finer ash
What is a pyroclastic flow
a hot mixture of gas, ash, and debris blown at high speeds
why does silica thicken lava
it reacts with oxygen to form a lattice structure which creates stringy chains
where does basaltic lava form
constructive plate boundaries
where does feltic (silica-rich) lava form
destructive plate boundaries
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