Mechanism, types and distribution of volcano

Published on 31 Jan 2025

A volcano typically takes the form of a mountain and serves as a geological feature through which molten rock, ashes, gases etc. emerges from the earth’s crust.

Mechanism of formation 

Formed when molten rock form the mantle erupts through the surface. The magma upon reaching the surface creates lava flows and deposits ash. With each successive eruption, additional layers of lava accumulate, gradually building up a mountain.

Types 

• Shield volcanoes: Formed during the lava flow of a low viscous fluid basaltic lava: creates lower profile and forms largest of all the volcanoes on earth. 

• Example: Mauna Loa in Hawaii and Erta Ale in Ethiopia 

• Composite/ strato volcano: They are steep sided high conical mountains with alternate layers of lava and ash with cooler and more viscous lava than basalt which results in explosive eruptions.

• Example: Mount Fuji in Japan , Mount Rainier in Washington U.S.A 

• Caldera: Most explosive of the earth’s volcanoes as the magma chamber supplying lava is huge and at close vicinity and have high viscous lava.

• Example: Yellow stone Caldera USA 

• Cinder cones: Result of eruptions of mostly small pieces of pyroclastic material that build up around the vent: most cinder cones erupts only once. 

• Example: Wizard island in crater lake national park

Distribution 

• Along subduction boundaries: Majorly in Pacific Ring of Fire which includes areas like Philippines, japan, Indonesia etc. 

• Example: Krakatoa in Indonesia, St. Helena in Washington

• Along sea floor spreading centres:

• In mid oceanic ridges –Example: Iceland 

• Areas of rifting continental plates – Example: Rift zone in East Africa 

• Hotspot volcanism: These are locations where individual plumes of magma rises through the crust and is situated away from tectonic margins

Example: Hawaiian island hotspot, Reunion Island, Easter island hotspot etc.

Tags:
Geography

Keywords:
Mechanism types and distribution of volcano volcano Mechanism of formation of volcano types of volcano Shield volcano Composite volcano strato volcano Caldera cinder cone distribution of volcano volcano hotspot

Syllabus:
General Studies Paper 1

Topics:
Physical Geography