Volcanoes

According to United Nations Office for Disaster Risk Reduction (UNDRR)- “Volcano is a natural hazard that occurs when magma from the earth’s interior is released through a vent or fissure, potentially cause damage and loss of life “.

Most of the Volcanoes in the world are found in three well defined belts –

1. Circum Pacific Belt -It is 40000 km horse shoe shaped zone of intense seismic and volcanic activity.It include regions of New Zealand, Australia, Philippines, Japan, Russia,USA etc .
2. The Mid World Mountain Belt -It is longest mountain range on earth, stretching over 65000 km which runs through the middle of Atlantic, Indian and Pacific oceans.
3. The African Rift Valley Belt -It is a zone of rifts abd faults stretching over 6000 km from Lebanon in north to Mozambique in south.

Reasons to support the Concentration of Volcanoes along the Pacific Ring of Fire –

1. Thinner crust making it easier for magma to rise and erupt .
2. Due to subduction and continental collision,it hosts numerous volcanic arcs ex-Indonesian Volcanic Arcs .
3. It consist regions of mantle plumes or hotspots ex-Hawaiian islands,Galapagos islands .
4. It is characterized by continental rifting (plates are pulling apart)ex-East African Rift System.
5. It has High Geothermal Gradient (Heat from the earth’s interior is closer to the surface).
6. It is a zone of intense seismic and volcanic activity resulting from convergence of tectonic plates (Pacific North American Plate), Divergence of Plates (East Pacific Rise)and transform plates (San Andreas Fault).

Understanding the global distribution and Pacific Ring of Fires unique geology will help in prediction,early warning system, evacuation plans, regular monitoring and disaster preparedness.