A volcano is an opening, or rupture, in a planet’s surface or crust, which allows hot magma, volcanic ash and gases to escape from below the surface.
Volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together.
By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth’s crust in the interiors of plates.
Incredible Volcano Eruption Photos
Undersea Volcano off the coast of Tonga March 18, 2009
NUKU’ALOFA, TONGA – MARCH 18: An undersea volcano is seen erupting off the coast of Tonga, sending plumes of steam, ash and smoke up to 100 metres into the air, on March 18, 2009 off the coast of Nuku’Alofa, Tonga. The volcano, which is situated approximately 6 miles off of the main Tongan island of Tongatapu, is one of around 36 undersea volcanos clustered in the area. There is currently no danger to residents of the island as the gases are blown offshore, and residents noted the eruptions began on Monday after a series of sharp earthquakes were felt in the capital.
Sarychev Volcano, Russia June 12, 2009
Sakurajima, Japan November 23, 2009
Puyehue Volcano, Chile
Soputan volcano spews thick smoke and heat clouds in Minahasa on June 6, 2008. A volcano erupted on Indonesia’s Sulawesi island on June 6, spewing smoke and sending heat clouds of debris down its slopes, a volcanologist said. Mount Soputan in North Sulawesi started to erupt June 6 at around 9:59 am (0159 GMT), sending heat clouds as far as four kilometres (2.5 miles) and throwing ash two kilometres into the air.
Puyehue Volcano, Chile June 5, 2011
Mt. Etna, Italy October 30, 2002
Mt. Etna, Italy April 8, 2010
Mt. Bromo, Indonesia September 28, 2006
Mt. Bromo, Indonesia December 11, 2010
Mt. Augustine, Alaska March 27, 2006
Mount Vesuvius, Italy April 26, 1872
Mount St. Helens, United States May 18, 1980
Mount Soputan Volcano, Indonesia June 6, 2008
Mount Rinjani, Indonesia 1994
Mount Redoubt, Alaska April 21, 1990
Mount Merapi, Indonesia November 3, 2010
Mount Merapi, Indonesia November 1, 2010
Mount Krakatoa, Indonesia May 6, 2008
Mayon Volcano, Philippines September 23, 1984
Kliuchevskoi Volcano, Russia October 24, 1994
Kliuchevskoi Volcano, Russia October 11, 1994
Eyjafjallajokul Volcano, Iceland April 17, 2010
A plume of ashes spewed by the Chaiten volcano as seen from the city of Chaiten, 1,200km south from Santiago, Chile on May 5, 2008. The volcano, which have erupted for the first time, has buried the surrounding region under a blanket of ash and has turned Chaiten into a ghost town, with its 4,000 residents –evacuated to nearby towns and cities– facing an uncertain future.
Cleveland Volcano, Alaska May 23, 2006
Chaiten Volcano, Chile May 6, 2008
Chaiten Volcano, Chile May 2, 2008
Comment with Facebook