Geography Volcanoes

place on a planet where some material from the inside of the planet makes its way through the planet's surface

fluid molten rock, part solid, part liquid, part gas

plume shape 500-1000 km wide between plate

when the upward pressure is exceeded by the downwards pressure, magma collects in magma chambers

• -high magma viscosity
• -towering, sustained plume
• -fast flowing lava
• -very disruptive
• -lots of pyroclastic material

• -not very destructive
• -not much pyroclastic material
• -sluggish flow of low viscosity lava
• -can be a fire fountain

• -not very dangerous
• -high viscosity magma
• -loud sounds
• -not very much lava
• -small eruption
• -no lava flows

• -no gas pressure
• -lava breaks through a crack and flows
• -curtain of lava spewing out
• -large flow of slow moving lava

large crater shaped basins that form when eruptions drain a magma chamber and the volcano collapses into the empty space

if the volcano erupted recently (200 years ago) then it is considered active and could explode again

if it erupted before historic times but within 10000 years ago it is considered dormant

if a volcano has no magma supply or it has not erupted for more than 10000 years it is considered extinct