Introduction to Volcanoes

How come volcanic activity formed? =)

Volcanic activity directly related to plate tectonics,most volcanoes being located near plate boundaries.

This relationship exists because spreading or sinking lithospheric plates at plate boundaries interact with other earth materials to produce molten rock,called,magma within the earth or lava when it erupts into the surface.

Pacific Ring of fire

Magma Formation 

• Magma is generated primarily within the asthenosphere
• decompression melting occurs when the overburden pressure athenosphere rocks is decreased by thinning of the overlying lithospheric plate causing of superheated rocks
• decompression melting also occurs when superheated rocks upwell from deep within the athenosphere as part of the hot spot.
• melting at subduction zone due to addition of volatiles to the athenosphere released from the downgoing oceanic plate.
• melting of the lithosphere due to the addition of heat carried by rising magma

For magma itself, it has its own properties :

1. Viscosity
2. Volatile content and eruptive behavior