- A volcano can go as far as 3000km deep.
- The volcanic rock pumice is the only rock that can float in water. It is usually grey and full of bubbly holes, which form when hot gases jet furiously out of the rock as it cools.
Strombolicchio in the Aeolian Islands of Italy
Photo by Danie Cutter
- The most formidable volcanoes are called supervolcanoes. A supervolcanic eruption can explode across thousands of miles and cause worldwide climatic changes, such as a drop in global temperature due to the release of tons of ash particles into the atmosphere. These monsters rear there ugly heads only ever few hundred thousand years, however. One of the biggest is in Yellowstone National Park, and scientists say it may be due for another eruption.
- Most volcanoes occur near the edges of tectonic plates, the massive rock slabs that make up Earth's surface. But some volcanoes, such as the Yellowstone supervolcano, lie over other "hot spots" where magma wells up from deep within the Earth.
Volcan de Agua, Antigua, Guatemala.
Photo by Danie Cutter
- Volcanoes can grow. As lava and ash accumulate, they add layers and height to the volcanic surface. This is one common way mountains are built.
- Volcanoes can become extinct. If scientists do not expect a volcano to ever erupt ever again, they consider it to be extinct. Volcanoes that are not currently active but may erupt again are labelled dormant.
By Simon Burford Twitter account @simonburford
- The sheer force of some volcanic eruptions can cause its magma chambers to collapse, forming a giant, bowl-shaped crater called a caldera.
- The biggest volcano on Earth is Hawaii’s Mauna Loa. One of the five volcanoes in Hawaii, it towers 13,000 feet above sea level. The Hawaiian Islands were actually created by a hot spot.
- Volcanoes make sunsets more colourful. When Alaska's Kasatochi volcano erupted in 2008, people all over the world saw unusually beautiful orange and coral hues in sunsets. This visual phenomenon is the result of fine ash particles in the atmosphere scattering the sun's rays.
Photo by @simonBurford: On the edge of the caldera - Vesuvius, Italy
- There are around 1510 'active' volcanoes in the world. We currently know of 80 or more which are under the oceans.
What are the three layers call that Planet Earth is made of?
The crust is the outer layer of the Earth. It is about 18 miles thick. It is the part we live on.
The second layer is called the mantle. It is about 1,800 miles thick.
- The Earth's crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. The plates sometimes move.
- Between the Earth's crust and the mantle is a substance called magma which is made of rock and gases.
- When two plates collide, one section slides on top of the other, the one beneath is pushed down. Magma is squeezed up between two plates.