Watch: Volcanoes
I鈥檓 in Italy visiting a very famous volcano called Mount Vesuvius.
A volcano is an opening in the Earth鈥檚 crust, which allows hot magma, ash and gases to escape from below the surface.
I鈥檝e been asked by my fellow explorers to get some rock samples from Mount Vesuvius, but it鈥檚 an active volcano, so I鈥檒l need to watch out for things like lava flow.
Lava is very hot molten or liquid rock, which reaches over 1,000 degrees. So I鈥檒l need to stay at a safe distance!
Volcanic ash. Clouds of ash can rise miles into the sky and block out light from the Sun, changing temperatures across the land and damaging aeroplanes in flight.
Pyroclastic flow. Hot gas, ash and rock mixed together to make a deadly cloud that flows down the side of the volcano.
It鈥檚 not all bad. They can also be tourist attractions!
The lava and ash from an eruption breaks down to provide valuable nutrients for the soil and is great for growing crops!
So, even though volcanoes can be very dangerous they play an important part in the lives of those living nearby!
Ok, I鈥檝e got my heat resistant suit, so I am ready to go!
Err鈥 I think?
What are volcanoes?
Volcanoes can look like small mountains or hills.
A volcano is an opening in the Earth鈥檚 crust that allows magma, hot ash and gases to escape.
Magma is molten rock - rock that is so hot it has turned into liquid.
When magma reaches the surface of the Earth, it is called lava. Lava comes out of the volcano as a volcanic eruption, along with gases and ash.
Where do you find most volcanic action?
Pieces of the Earth's crust, called tectonic plates, fit together a bit like a jigsaw and move very slowly.
Most sites of volcanic activity are along boundaries of tectonic plates.
Volcanic eruptions
Most volcanic eruptions are caused by tectonic plates moving towards each other.
Some volcanoes, like Mauna Loa in Hawaii are caused by hot spots in the Earth鈥檚 crust. These do not erupt violently and lava usually flows slowly out of them.
Eruptions from volcanoes can be very dangerous. They can produce:
- pyroclastic flows - fast moving clouds of hot ash, gas and rock
- ash clouds - small pieces of rock and glass that can be carried in the air for many kilometres
- volcanic bombs - large bits of very hot rock blown out of a volcano
Watch: What do volcanoes look like?
Activity: Quiz 鈥 Volcanoes
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