What are Volcanoes and Earthquakes?




Hot lava is shooting out of this erupting volcano.

What is a Volcano?

A volcano is a mountain with an opening that reaches down into the earth. Sometimes, when pressure inside the earth builds up, a volcano can erupt. An eruption occurs when lava shoots out and spills down a volcano. Lava contains ash, cinders, and hot, molten rock. When the hot lava cools, it gets hard and makes new rock. A volcanic eruption can cause damage and changes to the landscape.



This diagram shows where the three layers of earth are, along with where magma is inside of earth.

How Do Volcanoes Form?

The earth is made up of three layers. The most inner layer is the core, the middle layer is the mantle, and the outer layer is the crust. Volcanoes begin in the mantle, where hot, pasty rock called magma forms. Sometimes, magma gushes out of weak spots in the crust, but magma usually rises and comes out of the top opening of the volcano. Each time a volcano erupts, the volcano grows bigger.



Mount Saint Helens is located in Washington state.

Are there any volcanoes in the U.S.?

One of the volcanoes in the U.S. is Mt. Saint Helens. Mt. Saint Helens in a volcano located in the state of Washington in the United States. This volcano last erupted in 1980. The eruption lasted almost nine hours. Volcanic ash from the eruption spread all throughout the state- some ash even made to its way to the neighboring state of Idaho!



This earthquake happened in San Francisco, California and resulted in a large crack in the road.

What about Earthquakes?

Similar to volcanos, earthquakes also begin inside the earth. An earthquake is the sudden shaking or rolling of the earth. Beneath the earth's surface are plates. When these plates shift, the earth might shake, resulting in an earthquake. Some earthquakes are small and can barely be felt by humans. Others are larger and can cause damage to the surrounding areas.