Volcano's are a natural disaster. Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface. At the surface, it erupts to form lava flows and ash deposits. Over time as the volcano continues to erupt, it will get bigger and bigger.
This is a photo of where active volcanos are.
Magma from Ancient Greek is a mixture of molten or semi-molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets and some natural satellites.