Binsar Bakkara/AP
Mount Sinabung spews lava as seen from Jeraya, North Sumatra, Indonesia, on Sunday. Scientists have found that so-called supervolcanoes, erupt differently than ordinary volcanoes such as Sinabung.

Supervolcano eruptions are different from ordinary eruptions, say scientists

Supervolcano: Thousands of times more powerful than an ordinary volcano, the eruption of a supervolcano is driven by buoyant magma, according to new research. 

Not all volcanic eruptions are created equal, suggests a new report on supervolcanoes, the geologic monsters capable of spewing enough ash, pumice, and lava to create mass extinctions and mini ice ages. Bigger eruptions happen much less frequently than small ones, and different forces drive them upward through the Earth's crust.

The volcanoes we're familiar with, which regularly spit up smallish bits of lava  – like's Italy's Etna and Alaska's Pavlof – are triggered when semi-molten magma strains its earthen chamber to the point of cracking open, a process known as magma replenishment.

But a supervolcano – a volcano that spews at least 240 cubic miles of deposit, mostly recently during the Middle Paleolithic period – works a bit differently, according to the new findings published in Nature Geoscience. When it bursts open, it's because low-density magma has slowly accumulated beneath a volcano, pushing its way upward through thicker magma, like a beach ball released from under water. Or, like a lava lamp.

Scientists from the universities of Geneva, Bristol, and Savoie began to understand these different dynamics after running 1.2 million Monte Carlo experiments. Named for their casino-like use of random sampling, these computational algorithms play with variables like the volume of magma, its degree of crystallization, or the strength of a volcano's crust, to model systems full of uncertainty.

The study is a reminder that the explosions which have shaken human history  – from the ash entombment of Pompeii, Italy in the year 79 AD, to the devastating explosion of the Indonesian volcanic island Krakatoa in 1883 –  have been baking soda and vinegar compared to what continues to burble beneath the Earth's crust.

"We estimate that a magma chamber can contain a maximum of 35,000 km3 of eruptible magma," explained lead researcher Luca Caricchi, an Earth scientist at the University of Geneva. "Of this, around 10 per cent is released during a super-eruption, which means that the largest eruption could release approximately 3,500 km3 of magma.

According to the US Geological Survey, the most recent supervolanic eruption occurred about 74,000 years ago at the Toba Caldera in Sumatra, Indonesia. That explosion is estimated to have released 670 cubic miles of "ejecta" and left ash deposits in layers as thick as 2,000 feet.  Some scientists have speculated that the so-called Toba Catastrophe may also have left its mark on the human genome, by killing off most of the population and leaving behind only a few thousand breeding pairs.

Wim Malfait, another member of the research team from ETH Zurich, told BBC that out of sight probably doesn't mean out of danger. "This is something that, as a species, we will eventually have to deal with," he said.

"You could compare it to an asteroid impact – the risk at any given time is small, but when it happens the consequences will be catastrophic."

You've read  of  free articles. Subscribe to continue.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to

QR Code to Supervolcano eruptions are different from ordinary eruptions, say scientists
Read this article in
QR Code to Subscription page
Start your subscription today