Definitions

volcano - a cone shaped hill through which lava, ashes and gases may erupt (Phases: active, dormant, extinct)

vent - central pipe through which magma rises in the volcano

crater - surface rim of the volcano

magma - molten rock below the Earth's surface

lava - molten rock above the Earth's surface 700 -1200 degrees C

secondary cone - a smaller cone found on the side of the main volcanic cone, fed by small pipes branching from the vent or directly from the magma chamber

ash- volcanic rock dust less than 4mm in size

nuee ardente - a cloud of volcanic ash and pyroclasts

magma chamber - a body of molten rock found at the base of the vent

sill - a horizontal igneous intrusion

dyke - a vertical igneous intrusion

Pyroclastic - broken up rocks, volcanic fragments thrown up in an eruption (fire fragments)

Volcaninc bombs - a mass of ejected lava from a volcanic. A rugby ball shaped mass of molten rock larger than 65 mm