Super Volcanoes
How It Works|Issue 113

The world’s largest and deadliest volcanoes could envelop the whole planet in ash

Laura Mears
Super Volcanoes

Supervolcanoes are some of the most destructive natural structures on the planet. Classified only after they have erupted, they eject more than 1,000 cubic kilometres of lava in one go. They’re a thousand times more powerful than a standard volcano and so large that they could blanket the whole Earth in ash.

The ground collapses above them when they explode, and the scars that mark their positions consume so much of the landscape that they become virtually invisible. Yet bubbling pools of magma still seethe below the surface, venting hot steam and gas through the ever-weakening crust above.

Scientists grade volcanic eruptions on a scale of 0 to 8, known as the Volcanic Explosivity Index (VEI). The tiniest volcanoes at the bottom of the scale gently dribble magma, while the behemoths at the top spit out hundreds of tons at a time. There are only around 40 of these supervolcanoes worldwide, but just ten remain potentially active. They sit atop hotspots where magma leaks up from the Earth’s mantle. Bubbles of molten rock accumulate under the ground, building pressure that stretches the Earth at its seams. Between major eruptions, pockets of heat leak out as spurts of lava, water and gas, but eventually the pressure becomes too much. The crust melts and cracks, heaving above the liquid rock below.

When supervolcanoes erupt in earnest the impact is catastrophic. Lava explodes upwards or bursts out in sheets, forming vast splatters and fast-moving lava plains. The temperature of the liquid rock can be as low as 300 degrees Celsius or as high as 1,160 degrees Celsius. It might advance slower than walking speed or vent at more than 60 kilometres per hour, and it tears through everything in its path.

Denne historien er fra Issue 113-utgaven av How It Works.

Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.

Denne historien er fra Issue 113-utgaven av How It Works.

Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.

FLERE HISTORIER FRA HOW IT WORKSSe alt
THE POWER OF WATER
How It Works UK

THE POWER OF WATER

We're hooked on fossil fuels. But hydroelectric power is becoming an increasingly important replacement for coal and oil

time-read
4 mins  |
Issue 195
EXPLORING THE MOON'S CAVES
How It Works UK

EXPLORING THE MOON'S CAVES

Earth's rocky neighbour is home to a network of unexplored caves, and scientists are keen to take a peek inside

time-read
3 mins  |
Issue 195
HOW TO ELECT THE PRESIDENT
How It Works UK

HOW TO ELECT THE PRESIDENT

The campaigns, votes and elections that put someone in America's most powerful office

time-read
3 mins  |
Issue 195
WHAT IS MORNING SICKNESS?
How It Works UK

WHAT IS MORNING SICKNESS?

Why some pregnancies can cause nausea and vomiting

time-read
2 mins  |
Issue 195
20 WEIRDEST SCIENCE MYSTERIES
How It Works UK

20 WEIRDEST SCIENCE MYSTERIES

From dark matter to deep-sea crabs, science still can't fully explain these strange quirks of nature

time-read
10+ mins  |
Issue 195
THE TRIANGULUM GALAXY SHINES IN A NEW HUBBLE IMAGE
How It Works UK

THE TRIANGULUM GALAXY SHINES IN A NEW HUBBLE IMAGE

A nearby galaxy is shining with star formation in a new image from the Hubble Space Telescope.

time-read
1 min  |
Issue 195
The world's fastest charger fully powers smartphones in five minutes
How It Works UK

The world's fastest charger fully powers smartphones in five minutes

Scientists have revealed the fastest battery-charging technology in the world for smartphones, which can fully charge a smartphone in less than five minutes.

time-read
2 mins  |
Issue 195
Real-time brain stimulation slashes Parkinson's symptoms by half in trials
How It Works UK

Real-time brain stimulation slashes Parkinson's symptoms by half in trials

Brain stimulation that rapidly adjusts in real-time can dramatically reduce Parkinson’s symptoms, an early trial suggests.

time-read
2 mins  |
Issue 195
The hottest ocean temperature in 400 years threatens the Great Barrier Reef
How It Works UK

The hottest ocean temperature in 400 years threatens the Great Barrier Reef

The Great Barrier Reef is facing the hottest sea surface temperatures in four centuries.

time-read
2 mins  |
Issue 195
Massive medieval coin hoard worth about 150 sheep' discovered
How It Works UK

Massive medieval coin hoard worth about 150 sheep' discovered

Archaeologists in Germany have unearthed over 1,500 medieval silver coins after a citizen noticed what looked like ‘small metal plates’ while digging during a construction project.

time-read
2 mins  |
Issue 195