Knowra Lava flow Lava flow A stream or sheet of molten rock that moves across the ground during an eruption. Its shape and speed depend on lava composition, temperature, and terrain.
Lava viscosity : A measure of lava's resistance to flow, shaped chiefly by temperature, crystal content, and dissolved silica. Higher viscosity generally slows movement and produces thicker, shorter flows.
Lava : Molten or partly molten rock that has erupted onto Earth's surface. A lava flow is lava in motion across the ground.
Pāhoehoe : A basaltic lava-flow surface with smooth, billowy, or ropy forms. Its characteristic surface develops as fluid lava advances and deforms.
Lava-flow hazard : The risk that advancing lava will damage people, infrastructure, or property. Assessments focus on where flows may travel and what they can engulf.
Pyroclastic flow : A fast-moving, ground-hugging mixture of hot gas, ash, and volcanic fragments. Unlike a lava flow, it can race down slopes and overwhelm areas with little warning.
Lava tube : A tunnel formed when the surface of a lava flow solidifies while molten lava continues moving beneath it. Tubes insulate lava and can carry it far beyond the exposed flow front.
Magma : Molten or partly molten rock beneath Earth's surface, containing crystals and dissolved gases. Before eruption, the material that becomes a lava flow is called magma.
ʻAʻā : A basaltic lava-flow type with a rough surface of loose, jagged clinker. It shows how a flow's surface can break into sharp rubble during motion.
Lava-flow modeling : The use of physical or computational models to estimate lava-flow paths, extent, and arrival times. Models combine terrain and lava properties to support hazard maps and response plans.
Lahar : A volcanic mudflow made of water mixed with ash, rock fragments, and other debris. Lahars can travel through valleys where lava flows would not reach.
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