volcano types
...ounding rock, it gathers in a magma chamber. Any rise in pressure in the chamber may now push the magma upwards through cracks in the overlying rock. As the magma traveling up a crack approaches the surface, the pressure from the overlying rocks reduces; gases are released from the magma and expand so suddenly that an explosion rips open a funnel shaped vent (called a diatreme) to the surface. The lava that blasts out of the vent then cools, to form cinders, ash and dust - all referred to as "Tephra". A ring of tephra collects around the vent and, as the eruption subsides, this blocks up the diatreme. Volcanoes have erupted in many different places. Volcanoes have erupted in The Philippines, Java, Papua New Guinea & Hawaii and many other places. "The Ring of Fire", located around the Pacific Ocean, is 20 or so places with active volcanoes in them joined by one big imaginary line that forms a circle (or "Ring") when scaled down to the size on a map. Somewhere in the world an eruption occurs at least once a month. Whether it be big or small it doesn’t really matter at all. If it kills 1 person or 1 000 people it is still counted as an eruption. In ...