How are volcanoes formed?

Most volcanoes are formed when two plates meet. When they cause a gap in the earths crust, molten lava rises up between the cracks. This kind of volcanoe is on the oceans floor and is most likely visible. If the amount of lava or magma is large enough, it will create an ilsand. The state of Hawaii was formed by volcanic eruptions. There are at least 8 volcanoes on the islands of Hawaii. However there are many more benath the oceans surface around Hawaii. The other way a volcanoe is formed is by two plates coliding and one of the plates going under the other. Only a few volcanoes are formed like this on this planet but they are usually the most violent and dangerous. Sometimes volcanoes are formed in the middle of plates. These are called hotspots.