Hot melted rocks collect under the Earth's surface and when the pressure becomes too hard, the Earth's skin breaks, and a volcano erupts. The melted rock inside the Earth is called magma, but when it comes out in an eruption, it is called lava.Know More
Plates are like the Earth's skin. They are called the Earth's mantle, and they float on the magma. Sometimes the plates separate, and that creates even more red-hot liquid rock. The Earth has to relieve the pressure in the form of a volcanic eruption. After the eruption, the lava spreads out, cools down and hardens into rock, but hot magma remains under the surface.
In the Pacific Ocean, 75 percent of all volcanoes are located in an area called the Ring of Fire, where two of the Earth's plates meet. Some volcanoes are cone-shaped mountains, some are flat-topped like mountain plateaus, some have fissure vents, which are cracks where the lava escapes, and others bulge like domes. There are even volcanoes on the ocean floor and under the icecaps in Iceland.
Volcanoes also happen on other planets in the solar system. On Mars there is a volcano called Olympus Mons, and it is 373 miles wide and 13 miles high. The most volcanic activity in the solar system is on one of Jupiter's moons.Learn more about Volcanoes
A volcano is any place where magma from the Earth's interior breaks through its surface, as explained by How Stuff Works. Magma is molten rock that is partially liquid, partially solid and partially gaseous. Interaction between the plates that form the Earth's crust is one of the primary catalysts for creating magma.Full Answer >
The main vent of a volcano is the outlet chamber in the Earth's crust that allows hot magma to reach the surface. While secondary vents may form to alleviate the pressure caused by a magma chamber, the main vent is responsible for giving volcanoes their familiar cone shape.Full Answer >
The chief difference between a volcano and a mountain is that a volcano forms around a vent that allows magma to reach the surface of the Earth, while a mountain can be formed by a variety of different geological processes. Most mountains form as the result of plate tectonics, although some were formed by magma welling up from the mantle without breaking through the surface.Full Answer >
Mount Vesuvius, a volcano off the west coast of Italy, is one of the only active volcanoes on Europe's mainland. It is part of the Campanian volcanic arc, which rests on a tectonic boundary where the African plate is being subducted beneath the Eurasian plate.Full Answer >