Volcanoes

• Volcano - generally refers to an opening or vent in a planet's crust from which molten rock, ash, and gasses escape from below
• Active Volcano - It has errupted within the last 10,000 years
• Dormant Volcano - Has not erupted recently but could still be active
• Extinct Volcano - No longer erupts and is unlikely to do so again
• Shield volcano - A broad, gently sloping volcanic mountain built up by many flows of fluid lava that have spread outward as they cooled
• Composite (stratovolcano) - A steep-sided cone composed mainly of fragments of solidified lava and other ejecta that have been deposited around the vents during successive eruptions.
• Cinder cone volcano - A steep-sided volcanic hill formed when hot gas and ash are ejected explosively into the air above a central vent; the material falls back around the vent to form a conical pile of cinders (volcanic fragments).
• Cinder cone volcano - A small steep-sided volcano formed when hot gas and ash are ejected into the air during explosive eruptions.
• Composite volcano - Also called stratovolcano, this type of volcano consists of alternating layers of hardened lava, pumice, and volcanic ash. Composite volcanoes tend to be tall and symmetrical with steep sides and a summit crater.
• Hot spot - An area on Earth’s surface where magma rises close enough to melt rocks above it. Hot spots can form islands like Hawaii and Iceland
• Cinder Cone - A small volcano made mostly of cinders and ash; it forms when hot gas and ash are blown into the air above a magma chamber and then fall back down onto the ground near the vent
• Plate Tectonics - The theory that explains how the continents move across the earth's surface due to convection currents in the mantle
• Lava dome - A mound or mass of hardened lava that forms within a crater or on the flank of a volcano.
• Volcanic arc - A chain of volcanoes along an ocean trench caused by subduction.
• Convection Currents - Heated rock in the mantle moves upward towards the base of the crust, then sideways along the bottom of the crust, and finally downwards through the crust and back into the mantle.
• Lahar- a mudlflow that includes all debris along its path, which is usually a river valley composed of a very thick slurry, pyroclastic material, rock debris, and water
• Pyroclastic Flow - An extremely fast moving cloud of superheated gases (usually steam) mixed with solid fragments of rock ejected from a volcano during an eruption
• Ash Plume - A column of fine particles of rock and dust thrown up into the atmosphere by a volcanic explosion