What is the function of the peripheral system and its function? peripheral nervous system is all the nerves located outside the  central nervous system; connects the central nervous system to all  the parts of the body. 1 person found this useful.
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.
Quick Answer. A volcano erupts when the pressure of a subterranean pool of magma becomes great enough to crack the earth's crust. Whether the eruption results in a violent explosion or a slow seepage depends on several different factors, according to How Stuff Works. Continue Reading.