The Formation of Volcanoes

The formation of a volcano begins deep within the Earth where high temperatures cause rocks to melt and form a thick liquid known as magma. Being less dense than the surrounding solid rock, the magma rises and accumulates in a magma chamber. Over time, pressure builds up and the magma is forced out through openings in the Earth's surface, at which point it is referred to as lava.

The Three Main Types of Volcanoes

Broadly speaking, volcanoes can be classified into three main types.

1. Strato or Composite Volcanoes – These are large, steep-sided volcanoes that can reach heights of over 8000 feet. The lava they produce can flow at incredibly high speeds and temperatures, posing a significant threat to nearby life and property.
2. Shield Volcanoes – These volcanoes produce non-explosive eruptions and fast-flowing lava. While they can cause property damage, the risk of death or injury is low.
3. Dome Volcanoes – The lava produced by these volcanoes is thick and viscous, which means it doesn't travel far from the source.

The World's Most Dangerous Volcano

Mount Vesuvius, located in Italy, is widely considered the world's most dangerous volcano. According to the United States Geological Survey (USGS), there are roughly 1500 active volcanoes worldwide, of which around 500 have erupted in recorded history. Only a small fraction of these are considered to have the potential to cause catastrophic damage.

The information provided here will be useful to candidates preparing for the UPSC 2020 exam.

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