EOSC 114 Midterm: Volcanoes Learning Goals
Document Summary
Establish motivation for volcanological sciences define magma, lava, volcano - understand formation. Melts due to a decrease in pressure (not an increase in temperature) Molten rock material: melt + crystals + bubbles. Structure where magma is erupted at the earth"s surface. More subaqueous volcanoes (on mid ocean ridges) than subaerial. Magma is created by the melting of pre-existing rock in the earth"s interior (mantle & crust) It reaches the surface through fractures and erupts as lava/pyroclastic material (tephra) Magma moves through crack inside earth, either stored there or erupted later. 3 types of plate boundaries, and which volcanoes occur where. Mantle material rises in a dike, pressure decreases. Mantle material rises in cylindrical plume, pressure decreases. As magma rises, pressure decreases, bubbles begin to form. Viscosity fights bubble growth, but pressure rises inside bubbles until fragmentation occurs. Different types of volcanic eruptions - safest to most dangerous.
