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What makes volcanoes erupt? Are there any recent eruptions of any volcanoes close to Goleta?
Question Date: 2002-10-14
Answer 1:

Volcanoes form when hot rocks from inside the earth move up towards the surface. When the rocks are deep inside the earth, they are squished by pressure and therefore they are solid. When the rocks move up, there is less pressure on them and so they expand. Sometimes the change in pressure is so much that they can melt and become magma.

To make sense off this think of a marshmallow in your hand. If you squeeze the marshmallow in your hand, it will get smaller. Your hand is putting pressure on the marshmallow. Now, if you open your hand and relieve the pressure, the marshmallow will go back to its normal size, or expand.

>When rocks melt, gas escapes. Gases take up more space than liquids or solids, so they increase the pressure. The gas that escapes will build up until it increases the pressure on the magma to the point where the magma will find a crack or tunnel and erupt.

Unfortunately for geologists (because we like to study volcanic eruptions), but luckily for all of us that live here, there have not been any recent volcanic eruptions near Goleta or Santa Barbara. The closest recent eruptions have been in Mexico and in Washington, Mount St. Helens.

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