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== Volcanoes are generally found where tectonic plates are diverging or converging. a mid-oceanic ridge, 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 earths crust in the interiors of plates, eg. in the East African Rift, the Wetts Gray-Clearwater volcanic field and the Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "Plates hypothesis" volcanism. == == Intraplate volcanism has also been postulated to be caused by mantle plumes. These so-called hotspots for example Hawaii, are postulated to arise from upwelling diapirs from the core-mantle boundarym, 3000 kilometers deep in the earth. ==

There are lots of differnt types of volcanoes, such as Subglacial volcanoes, Mud volcanoes, Supervolcanoes, Submarine volcanoes and more.
== Subglacial volcanoes develop underneath icecaps. They are made up of flat lava which flows at the top of extensive pillow lavas and palagonite. when the icecap melts, the lavas on the top collapse, leaving a flat-topped mountain. These volcanoes are also called table mountains, tuyas or (uncommonly) mobergs. == == Mud volcanoes or mud domes are formations created by geo-excreted liquids and gases, although there are several processes which may cause such activity. The largest structures are ten kilometres in diameter and reach 700 metres high. == == ﻿A supervolcano is a large volcano that usually has a large caldera and potentially produce devastation on an enormous, sometimes continental scale. Such eruptions would be able to cause several cooling of global temperatures for many years afterwards because of the huge volumes of sulphur and ash erupted. == == Submarine volcanoes are common features on the ocean floor. Some are active and, in shallow water, disclose their presence by blasting steam and rockey debris high above the surface of the sea. Many others lie at such great depths that the tremendous weight of the water above them prevents the esplosive release of steam and gases, although they can be detected by hydrophones and discoloration of water because of volcanic gases. ==



  