How many kinds of volcanoes are there?
Volcanoes are hills or mountains that are usually cone-shaped. A volcano is built around a vent that leads down to a reservoir of molten rock, or magma, below the surface of the Earth. When a volcano erupts, the molten rock is forced upward by gas pressure until it breaks through weak spots in the Earth’s crust. The magma either emerges as a lava flow (when molten rock surfaces above ground it’s called “lava”) or shoots into the air as clouds of lava fragments, ash, and dust. The accumulation of debris from eruptions causes the volcano to grow in size. There are four kinds of volcanoes: Cinder cones are made of lava fragments. They have slopes of 30 degrees to 40 degrees and seldom exceed 1,640 feet (500 meters) in height. Sunset Crater in Arizona and Paricutin in Mexico are examples of cinder cone volcanoes. Composite cones are made of alternating layers…
