Why does volcano eruption

Ultimately, the size of an eruption will depend on the thickness of the magma, the density of gases it contains and the amount of new magma being pushed into the magma chamber. Basaltic lava allows gas to escape easily, resulting in smaller eruptions, while andesitic and rhyolotic lava makes it harder for the gas to escape, leading to larger eruptions. Lava is often thought to be the main danger of a volcanic eruption, but this is not the case.

Numerous hazards result from eruptions and they can have a range of consequences. The most dangerous are the pyroclastic clouds, which destroy anything in their path. Other hazards include ash clouds, ash rain, mudslides, earthquakes, tsunamis, odd weather patterns and glacial flooding. Originally published by Cosmos as Why do volcanic eruptions occur? Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science.

Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Please support us by making a donation or purchasing a subscription today. Share Tweet. What causes a volcanic eruption? Forecasting involves probable character and time of an eruption in a monitored volcano.

The character of an eruption is based on the prehistoric and historic record of the volcano in question and its volcanic products. For example, a violently erupting volcano that has produced ash fall, ash flow and volcanic mudflows or lahars is likely to do the same in the future. An excellent example of successful forecasting occurred in Volcanologists from the U. Geological Survey accurately predicted the June 15 eruption of the Pinatubo Volcano in the Philippines, allowing for the timely evacuation of the Clark Air Base and saving thousands of lives.

Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. Volcanoes don't run on a timetable like a train. The deadliest eruption in recorded history was the explosion of Mount Tabora in Indonesia. The blast was one of the most powerful ever documented and created a caldera —essentially a crater—4 miles across and more than 3, feet deep.

A superheated plume of hot ash and gas shot 28 miles into the sky, producing numerous pyroclastic flows when it collapsed. The eruption and its immediate dangers killed around 10, people.

But that wasn't its only impact. The volcanic ash and gas injected into the atmosphere obscured the sun and increased the reflectivity of Earth, cooling its surface and causing what's known as the year without a summer. Starvation and disease during this time killed some 82, more people, and the gloomy conditions are often credited as the inspiration for gothic horror tales, such as Mary Shelley's Frankenstein.

Although there have been several big eruptions in recorded history, volcanic eruptions today are no more frequent than there were a decade or even a century ago.

At least a dozen volcanoes erupt on any given day. As monitoring capacity for—and interest in—volcanic eruptions increases, coverage of the activity more frequently appears in the news and on social media. All rights reserved. How do volcanoes form? Share Tweet Email. Why it's so hard to treat pain in infants. This wild African cat has adapted to life in a big city. Animals Wild Cities This wild African cat has adapted to life in a big city Caracals have learned to hunt around the urban edges of Cape Town, though the predator faces many threats, such as getting hit by cars.

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Heather Handley , Macquarie University. Why do volcanoes erupt?