1. Volcanoes

2. Volcanoes are openings in the Earth’s surface. When they are active they can let ash, gas and hot magma escape in spectacular eruptions.

3. Where do you find them?

4. Volcanoes are usually located where tectonic plates meet. This is especially true for the Pacific Ring of Fire, an area around the Pacific Ocean where over 75% of the volcanoes on Earth are found.

5. Ring of Fire

6. They can also form in areas that contain abnormally hot rock inside the Earth. Known as mantle plumes, these hotspots are found at a number of locations around the globe with the most notable being in Hawaii.

7. While we certainly have some big volcanoes here on Earth, the biggest known volcano in our solar system is actually on Mars. Its name is Olympus Mons and it measures a whooping 373 miles wide and 13 miles high !

8. Olympus Mons is 3 times the size of Mt. Everest!

9. The softened rock is squeezed by all the rock above it, and it eventually reaches a magma chamber a few miles below the volcanic vent. As the magma enters cooler surroundings, it gets a boost from buoyancy. As the magma continues rising, falling pressure releases high-pressure gas that was trapped inside it, and the volcano explodes.

10. There are openings in the surface of the Earth. Hot magma from the mantle is being turned about under the planet. Eventually, it finds the escape route, and explodes through the volcano.

11. Mount St. Helens

12. On May 18, 1980, a “sleeping giant” woke up. The release of pressure over the magma chamber created a glowing cloud of gas and rock debris blew out of the mountain face. The blast was so strong that all the trunks of trees neatly aligned to the north. The area devastated by the direct blast force covered an area of nearly 230 square miles

14. Shortly after, a second, vertical explosion occurred at the summit of the volcano, sending a mushroom cloud of ash and gases more than 12 miles into the air. The cloud of ash darkened the skies, causing streetlights to come on as far away as Spokane, Wash., more than 300 miles away. Ash continued to erupt for more than nine hours. Ultimately, an estimated 540 million tons of ash drifted up to 2,200 square miles settling over seven states

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