The sight of a volcano erupting has to be equally one of the most amazing and scary sights in nature. A volcano is a place on the Earth's surface (or any other planet or moon's surface) where molten rock, gases and debris like ash and dust, erupt through the earth's crust. Volcanoes vary quite a bit in their structure - some are cracks in the earth's crust where lava erupts, and some are domes, shields, or mountain-like structures with a crater at the summit.
Magma is molten rock within the Earth's crust. When magma erupts through the earth's surface it is called lava.
The largest volcano on Earth is Hawaii's Mauna Loa. Mauna Loa is about 10 km tall from the sea floor to its summit (it rises about 4 km above sea level). It also has the greatest volume of any volcano - 42,500 cubic kilometres.
Mauna Loa - J Griggs
But apart from representing an amazing force in nature, volcanoes have shaped our past and they influence our present.
Because of a volcanic eruption, we have a snapshot of what life was like in Roman towns. Archeologists have uncovered the remains of Pompeii and nearby Herculaneum, which were destroyed by the eruption of Vesuvius in Southern Italy, in AD 78.
Pompeii - R Decker
While today, it is thought that approximately 10% of the World's population live within `danger range' of an active volcano.
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Volcanoes