Volcanic Landforms

A volcanic landform is characterized by the type of material it is made of. Later processes modify the original landform to other forms. Volcanic landforms include the following:

• caldera—very large, cauldronlike depression that is usually formed by the collapse of land following a volcanic eruption. Calderas are enclosed depressions that collect rainwater and snowmelt, and thus lakes often form within a caldera.

• geyser—a hot spring characterized by intermittent discharge of water ejected turbulently and accompanied by steam.

• lava—molten rock.

• lava spine—an upright cylindrical mass of lava caused by the upward squeezing of pasty lava inside a volcanic vent.

• lava tube—a natural conduit through which lava travels beneath the surface of a lava flow, expelled by a volcano during an eruption.

• maar—a broad, low-relief volcanic crater that is caused by an explosion caused by groundwater coming into contact with hot magma.

• malpais—a landform characterized by eroded rocks of volcanic origin in an arid environment.

• mamelon—a hill formed by eruption of stiff lava.

• mid-ocean ridge—an underwater mountain range, typically having a valley known as a rift running along its spine, formed by plate tectonics.

• oceanic trench—narrow topographic depressions of the sea floor.

• pit crater—a depression formed by a sinking of the ground surface lying above a void or empty chamber.

• pseudocrater—a volcanic landform that resembles a true volcanic crater but differs in that it is not an actual vent from which lava has erupted.

• subglacial mound—a type of subglacial volcano that forms when lava erupts beneath a thick glacier or ice sheet.

• tuya—a distinctive, flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet.

• volcanic dam—a natural dam produced by volcanic activity.

• volcanic field—a spot of the Earth’s crust that is prone to localized volcanic activity.

• volcanic plateau—a plateau produced by volcanic activity.

• volcanic plug—a volcanic landform created when magma hardens within a vent on an active volcano.