A volcano is an opening in the Earth’s crust through which magma (molten rock) erupts. Some volcanoes are cone-shaped mountains with a crater at the summit. Others can be just a crack in the ground, called a fissure. A volcano may erupt lava, ash, dust, fumes, gas and lumps of rock called volcanic bombs.

Hawaiian eruptions

In other volcanic eruptions, the lava oozes out gently, like boiling syrup. It spreads out over a wide area. As it cools it tuns into solid rock. Hawaiian eruptions are named after the volcanoes on the Hawaiian Islands in the Pacific, which erupt like this. Mount Etna in Sicily is another example of a Hawaiian eruption.

Strombolian eruptions

There are some volcanoes that erupt all the time. Stromboli, in the Aeolian Islands of Italy, has been erupting for centuries. In these volcanic eruptions, lava, along with lumps of rock, is thrown high into the air.

An active volcano erupts lava, ash and dust frequently. When a volcano has not erupted for many years, it is called a dormant volcano. This type of volcano may erupt again some time in the future. When eruptions stop altogether, the volcano is described as extinct.