Geography

The nature of the vent-Is it linear or central vent? The type or nature of the lava -Is it a mobile or viscous lava? The character of the earth crust through which the lava escapes.

Volcanic eruption can be classified into three namely Active, Dormant and Extinct volcanoes: Active Volcanoes are volcanoes that are still and frequently erupting e.g. Cameroon Mountain, Fujuyama in Japan etc. Dormant Volcanoes are volcanoes that show sign of eruption in future: e.g. St. Helen, Canary Islands and Cape Verde Islands. Extinct Volcanoes are volcanoes that …

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EXTRUSIVE VULCANICITY: This is the solidification of molten magma directly on the surface of the earth crust to form distinctive features like composite Cones, Cinder Cones, Lava Cones or Shield Volcanoes, Lava Dome and Calderas.

INTRUSIVE VULCANICITY: This is the solidification of molten magma within the crust which forms various features like Dykes, Siulls, Laccoliths, Lopolith, Phacolith, Batholith, Volcanic necks and Dike ridges.

VULCANICITY OR VULCANISM: This is all the processes by which, gaseous materials/molten magma beneath the earth, forces its way into the cracks of the earth’s crust and escapes through fissures onto the surface of the earth. Volcaism is associated with areas where mountain building has taken place. There are two kinds of volcanism namely intrusive …

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Volcanoes are hills or mountains that are formed when hot molten rock called lava, from inside the earth pushes up through the earth’s crust. Gases produce volcanic eruption.