Volcano! - Beth Geiger
A Dangerous Job
Joanne Green walks by a glowing river. This river has no water, however. Instead, it is made of hot liquid rock, or lava.
The lava river is extremely hot, and so are the rocks surronding it. "If you aren't careful," she says, "You'll melt your boots on the hot rock. Or worse!"
Green is used to these dangers. They are part of her job. She is a volcanologist, a scientist who studies volcanoes.
Green is studying Kilauea, a volcano in Hawaii. Green studies other volcanoes, too. Earth has thousands of them.
Volcanoes On Earth
Most people think that volcanoes are simply large mountains thats pour out lava. But a volcano actually starts deep beneath Earth's surface, or crust.
The laver of rock below the Earth's crust is called the mantle. But the pressure and high temperature near the center of the Earth change the rock to liquid. The pressure can force the liquid rock upward. It moves up through cracks in the Earth's crust. This can form a volcano.
It's About The Lava
Anout 1,500 of Earth's volcanoes are active. An active volcano is one that can erupt lava.
Some volcanoes make runny lava. The lava flows fast, like pancake batter. It piles up in thin layers. Over time, it forms low, wide mountains.
Other volcanoes erupt thick lava. It flows slowly, like toothpaste. It piles up in thick layers. Over time, it forms tall, steep mountains.
The Ring Of Fire
Volcanoes are found all over Earth. Some form on land. Others rise up from the bottom of the ocean. Most volcanoes are near the Pacific Ocean. They form a circle of volcanoes known as the Ring of Fire. These volcanoes are found in areas where big pieces of Earth's surface, of platesl meet. Many volcanoes are formed along such as plate boundaries.
Living With Volcanoes
Many people live near volcanoes. Some live close to the base of the mountains. Others farm nearby land. Ash from volcanoes if good for soil, so crops grow well.
A Dangerous Surprise
Living near a volcano can be dangerous, though. Volcanoes can erupt without warning.
That is just what happened in 1980 in Washington. On May 18, a volcano named Mount St. Helens erupted. Hot ash and steam blasted out of the volcano.
Few people were ready for it. Even scientist didn't knowit would happen that day. The volcano had not erupted since 1857.
The burning ash poured down the mountain, killing all the trees and wildlife in its path. The blast produced million of tons of dust that covered 230 square miles.
Life Renturns
More than 20 years have passed since that day. Trees have now grown back. Animals live in the forest. Life has returned to Mount St. Helens. The people there will not forget what happened, though.
A Force On Earth
Volcanoes are all over the world. Some are active and some are not. Some, like Mount St. Helens, could erupt without much warning. Volcanoes are one of the force on Earth that we live with but can't control.
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