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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 .
Many monogenetic volcanoes are cinder cones, often with lava flows, such as Parícutin in the Michoacán-Guanajuato volcanic field, which erupted from 1943 to 1952. Some monogenetic volcanoes are small lava shields, such as Rangitoto Island in the Auckland volcanic field. Other monogenetic volcanoes are tuff rings or maars. A monogenetic field ...
Augustine Volcano (Alaska) during its eruptive phase on January 24, 2006. A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
A volcanic field is an area of Earth's crust that is prone to localized volcanic activity. The type and number of volcanoes required to be called a "field" is not well-defined. [1] Volcanic fields usually consist of clusters of up to 100 volcanoes such as cinder cones. Lava flows may also occur.
Pahoehoe lava is a relatively smooth lava flow that can be billowy or ropey. They can move as one sheet, by the advancement of "toes", or as a snaking lava column. [10] A'a lava flows are denser and more viscous than pahoehoe, and tend to move slower. Flows can measure 2 to 20 m (7 to 66 ft) thick.
In some cases, a lava plateau may be part of a single volcano. An example is the massive Level Mountain shield volcano in northern British Columbia , Canada , which covers an area of 1,800 km 2 (690 sq mi) and a volume of 860 km 3 (210 cu mi).
El Golfo volcano's later lava flows covered the remains of Tiñor volcano. At its maximum development, El Golfo volcano was about 2,000 m (6,600 ft) high and about 20 km (12 mi) in diameter, with a surface area slightly larger than present-day El Hierro and about twice the area that Tiñor volcano had covered.
Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from 800 to 1,200 °C (1,470 to 2,190 °F). The volcanic rock resulting from subsequent cooling is also often called lava. A lava flow is an outpouring of lava during an effusive eruption.