Volcanoes can be extremely dangerous. The power a volcano has can be catastrophic! Earth alone has about 1,500 currently active volcanoes. The shape of a volcano may remain unchanged for centuries, and can change drastically in a matter of minutes. Most of the Earth’s volcanoes are seamounts; seamounts are volcanoes that are hidden beneath the surface of the ocean. Volcanoes are mainly vents and holes in the surface of the earth where heated materials escape from underground.

One type of volcano is a stratovolcano (also called compostite volcanoes). They have a very symmetrical cone shape. They can have slopes of up to 30 degrees at the summit. They’re mostly built up with layers of lava and pyroclastic. One example of a stratovolcano would be Mount Fuji in Japan. They may rise as much as 8,000 feet above their bases.

Shield volcanoes are built up of almost entirely lava flows. The flowing of lava pours out in many directions from the summit vent. This created a broad domical shape, which looks much like that of a warrior’s shield. A couple of the world’s largest volcanoes are shield volcanoes. In California, there are many shield volcanoes that have a diameter of around 3 or 4 miles with a height of 1,500 to 2,000 feet. Mauna Loa, located in Hawaii, is a shield volcano, and it’s the largest active volcano in the world.

Cinder cones are a pretty simple type of volcano. They are built from particles of lava that come from a single vent. As the lava is thrown into the air by pressure, it breaks into small fragments that turn into a solid and become cinders around the vent to make an oval cone. Almost all cinder cones have a bowl-shaped crater at the summit. They hardly ever rise more than a thousand feet in height. In western North America, there are a large variety of cinder volcanoes.

The Ring of Fire is a geographically active belt around the Pacific Ocean. Over 75 percent of the planet’s volcanoes are located there. Since they’re in the ocean, they are seamounts. The Ring of Fire is on the borders of the Pacific Plate, and is also around many other tectonic plates. Around the Ring of Fire, the Pacific Plate is colliding with and going underneath many other plates. This is called subduction. The energy created by the plates melts rock into magma. The magma then rises on the surface and forms into lava, which makes a volcano.