Volcanoes

Volcanoes are classified on the basis of nature of eruption and the form developed at the surface. Major types of volcanoes are as follows: -


Shield Volcanoes: -
Shield Volcanoes are the largest of all the volcanoes on the earth. Barring the basalt flows.


Composite Volcanoes:-
They are characterized by eruptions of cooler and more viscous lavas than basalt. These volcanoes often result in explosive eruptions, large quantities of pyroclastic material and ashes find their way to the ground.




Caldera: -
These are the most explosive of the earth’s volcanoes. They are usually so explosive that when they erupt they tend to collapse on themselves rather than building any tall structure. The collapsed depressions are called calderas. Their explosiveness indicates that the magma chamber supplying the lava is not only huge but is also in close vicinity (area near or surrounding).


Flood Basalt Provinces: -
These volcanoes outpour highly fluid lava that flows for long distances. Some parts of the world are covered by thousands of sq. km of thick basalt lava flows. The Deccan Traps from India, presently covering most of the Maharashtra plateau, are a much larger flood basalt province. It is believed that initially the trap formations covered a much larger area than the present.


Mid-Ocean Ridge Volcanoes: -
These volcanoes occur in the oceanic areas. The central portion of this ridge experiences frequent eruptions.