Volcano facts

Last updated at 15:30
Mount Merapi in IndonesiaAP

One in 10 people in the world live within 'danger range' of an active volcano.

There are about 1,510 'active' volcanoes in the world. Volcanologists disagree on what comes under the term 'active', but 1,510 volcanoes have erupted in the last 10,000 years, which means they are active in the world of volcanoes. There are thought to be many more volcanoes on the sea bed.

The biggest volcano in the world is Mauna Loa in Hawaii. Its whole volume is about 80,000 cubic kilometres.

Sometimes lightning is seen in volcanic clouds. It's not clear why this happens but it could be to do with lots of hot particles bashing into each other, causing static charges.