A volcano is a hazardous event which is associated with emergence of hot lava below the surface of earth crust. This is caused by the development of heat and pressure below the surface of earth crust. The hot lava emerge out with a explosion.
A stratovolcano is also called as the composite volcano. It appears in the form of cone. It is associated with many layers or strata of hardened lava, ash, pumice and tephra. The lava flowing from the stratovolcanoes typically cools and hardens before it spreads too far from it's site of origin, because of high viscosity.
