Natural conduit through which lava flows beneath the solid surface
Valentine Cave, a lava tube in Lava Beds National Monument, California shows the classic tube shape; the grooves on the wall mark former flow levels.Thurston Lava Tube in Hawaii Volcanoes National Park, Hawaii. The step mark, more visible on the right wall, indicates the depth at which the lava flowed for a period of time.Rare characteristics of lava tubes are lava pillars. This is the Manjanggul lava pillar located in the Manjanggul lava tubes, on the island of Jeju-do, Korea.Lavacicles on the ceiling of Mushpot Cave in Lava Beds National MonumentClose-up of a skylight on a coastal plain, with lava stalactites forming on the roof of the tube, Hawaii Volcanoes National ParkEntrance of a lava tube, Big island, Hawaii
A lava tube, or pyroduct,[1] is a natural conduit formed by flowing lava from a volcanic vent that moves beneath the hardened surface of a lava flow. If lava in the tube empties, it will leave a cave.
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