I have often wondered how long it would have taken for the earth to tear itself to pieces in one vast explosion if the safety valves afforded by volcanoes did not exist. In Britain we are lucky not to suffer the more extreme forms of natural disaster, of which a volcanic eruption in full swing is probably the most visually impressive, but many countries experience their varied effects.
As with all sciences, volcanology has its classifications, the simplest being extinct, dormant or active, while a Richter Scale-like Volcanic Explosivity Index (VEI) was devised in 1982 by two American geologists to measure relative eruption power on a scale of 1-8. Volcanoes are also divided into three main
