1 Jun 2021, 16:03 BST
When engineers began drilling into an Icelandic volcano named Krafla, things took a turn for the weird. The team’s objective was to approach the boundary of a magma reservoir 2.5 miles below the surface, tapping into superheated fluids that could produce geothermal energy. But when the drill was just over a mile down, molten rock began creeping up the drill.
On that brisk spring day in 2009, the engineers had accidentally hit a pocket of magma sitting right below the surface that no one knew was there.
Krafla is “one of the best studied volcanoes on the planet,” says Hugh Tuffen, a volcanologist at Lancaster University in the United Kingdom who wasn’t involved with the research. It has been repeatedly surveyed using a range of techniques, so scientists thought they had a decent grasp of its underground workings. “It’s remarkable that this magma was able to hide.”
Scientists' ability to estimate eruption risks is largely reliant on knowing where pools of magma are stored, deep in the Earth's crust. But what happens.
Let s talk magma: how small is too small to detect?
New research published recently in
Geology reports on the discovery of shallow pools of magma lying just beneath the Earth’s crust that are too small to be seen with traditional volcano measuring equipment. The study contemplates the disparities between samples of a quenched magma that had formed smooth volcanic glass, and samples of rocks from an eruption from that same volcano, Krafla, in 1724. When we looked at the compositions from 1724, we found an almost perfect match for what was sampled during the drilling, says lead author Shane Rooyakkers from GNS Science in New Zealand. That suggests that actually, this magma body has been there since 1724 and has previously been involved in an eruption at Krafla. So that raises the question of, Why did geophysics not pick it up?