Five interesting facts about Volcanoes

It is believed that more than 80% of the earth’s surface is volcanic in origin.

By Salome Phelamei | Updated: Nov 18, 2013, 21:35 PM IST

What is volcano?

A volcano is an opening or rupture, in the surface or crust of the Earth, which allows hot lava (magma erupting from a volcano is called lava), volcanic ash and gases to escape from the magma (molten rock) chamber below the surface. Eruption occurs when pressure builds up.

Below are five interesting facts about volcanoes:

1. The eruption of Mount Tambora in Indonesia is the deadliest volcano ever recorded by humans. The explosion was so loud that it was heard on Sumatra Island more than 1,200 miles (1,930 km) away. The death toll was estimated to be at least 71,000 people, of whom 11,000-12,000 were killed directly by the eruption and the rest to starvation and disease.

2. It is believed that more than 80% of the earth’s surface is volcanic in origin. The sea floor and some mountains were constituted by innumerable volcanic eruptions. The earth’s atmosphere is formed by the gaseous emissions from volcano.

3. A volcano is active if it erupts lava, releases gas or shows seismic activity. A volcano is inactive or dormant if it hasn’t erupted for a long time but could again one day. However, an extinct volcano will never erupt again. According to the US Geological Survey, there are about 1,500 potentially active volcanoes worldwide, not including the continuous belt of volcanoes on the ocean floor.

4. Volcanic ash can be a threat to aircraft, in particular those with jet engines where ash particles can be melted by the high operating temperature. Volcanic ash can also cause damage to lungs of elderly, babies and people with respiratory problems. The danger vicinity around a volcano covers about a 20-mile radius.

5. An erupting volcano can cause tsunamis, flash floods, earthquakes, mudflows and rockfalls.