Volcanoes 101
Most volcanoes look like peaceful mountains, unless they've erupted recently. When Mt. Saint Helens in Washington erupted in 1980 it hadn't erupted for 123 years. People just thought it was a beautiful mountain. Although an eruption can happen without warning, lava flows from volcanoes rarely kill people because they move slowly enough for people to get out of the way. However, blankets of ash can be thick enough to suffocate plants, animals and people.
Shooting Lava
One of the most interesting and breathtaking things about a volcano eruption is how high lava shoots out. Large explosive eruptions can shoot lava ash to heights of 25 miles (40 km.) Volcanoes erupt because of pressure. Deep within the Earth it is so hot that some rocks slowly melt and turn into a thick substance called magma. Because it is lighter than the solid rock around it, magma rises and collects in magma chambers. Eventually some of the magma pushes through vents and shoots into the sky. To get a visual, shake a can of pop and then get someone else to open it. Magma that has erupted out of a volcano is called lava. Eruptions can last anywhere from a few hours to 100,000 days. Most seem to last about 49 days.
It's All Science Fiction
The stories about going down into the opening of an old volcano are all pretty much science fiction. The final stage of most eruptions includes lava, ash or debris falling back down into the hole. There usually are no long chambers to climb down. The deepest depressions are called calderas, which are about 1 km across (1000 meters.) So, even if you did walk a few hundred meters into a volcano, it wouldn't feel like you were going down a shaft or something because calderas are so wide.
Active Volcanoes
There are about 26 types of volcanoes. Some of the most common types are shield volcanoes, cinder cones and submarine volcanoes. Right now there are about 1500 active volcanoes in the world. Active means the volcano has a possibility of erupting again. The number of inactive volcanoes is unknown because they haven't all been counted yet. There are also volcanoes on the ocean floor and on Mars and Venus that shouldn't be forgotten.Kilauea, in Hawaii, is the world's most active volcano. It has been erupting continuously since 1983.
Did you know most diamonds come from old, deeply eroded volcanoes? To be more specific, from a rare type of volcanic structure called kimberlite pipes. It takes heat and pressure to turn carbon into diamonds. They are then brought to the surface of Earth in volcanoes.
Have you ever seen a volcano up close?
