Washington, May 30 : Scientists have simulated in lab the secret process that can stir up ordinary volcanic eruptions into so-called "super volcanoes".
Ben Kennedy and Mark Jellinek of UBC's (University of British Columbia's) Dept. of Earth and Ocean Sciences, and John Stix of McGill University's Dept. of Earth and Planetary Sciences conducted the experiment.
Using volcanic models made of Plexiglas filled with corn syrup, the researchers simulated how magma in a volcano's magma chamber might behave if the roof of the chamber caved in during an eruption.
"The magma was being stirred by the roof falling into the magma chamber," said Stix. "This causes lots of complicated flow effects that are unique to a super volcano eruption," he added.
Super volcanoes are orders of magnitude greater than any volcanic eruption in historic times. They are capable of causing long-lasting change to weather, threatening the extinction of species, and covering huge areas with lava and ash.
"There is currently no way to predict a super volcano eruption," said Kennedy, a post-doctoral fellow at UBC and lead author on the paper.
"But this new information explains for the first time what happens inside a magma chamber as the roof caves in, and provides insights that could be useful when making hazard maps of such an eruption," he added.
The eruption of Mount Tambora in Indonesia in 1815 - the only known supervolcano eruption in modern history - was 10 times more powerful than Krakatoa and more than 100 times more powerful than Vesuvius or Mount St. Helens.
It caused more than 100,000 deaths in Indonesia alone, and blew a column of ash about 70 kilometers into the atmosphere. The resulting disruptions of the planet's climate led 1816 to be christened "the year without summer."
"And this was a small supervolcano," said Stix.
"A really big one could create the equivalent of a global nuclear winter. There would be devastation for many hundreds of kilometres near the eruption and there would be would be global crop failures because of the ash falling from the sky, and even more important, because of the rapid cooling of the climate," he added.