Discuss the processes involved in volcanism. Highlight the major volcanic regions in the world and their associated tectonic settings.

Volcanism is geo dynamic natural process whereby the molten magma erupts through 'vent' as lava. Process involved in volcanism: a) Convection currents of molten magma - contact circulation of current in earth's interior, b) Presue of weaker lithospheric zone, c) Escape of molten magma through the weaker zone, d) Flow of lava & other volatile materials like pyrite, sulphur & nitrogen dioxide, etc through vent. e) Formation of various extruded & internal landforms due to volcanoes [EX] Basalithi, Dykes, etc.