Massive Lake Hiding Under a Volcano Could Explain Secrets Behind an Eruption

A massive lake was found beneath a dormant volcano in Bolivia, South America.

Scientists from the University of Bristol and partner universities in Germany, France, Canada and Wales have discovered a large magmatic lake 15 kilometers below the Cerro Uturuncu volcano in the Bolivian Altiplano.

"The Bolivian Altiplano has been the site of extensive volcanism over past 10 million years, although there are no currently active volcanoes there," Jon Blundy, a professor at the University of Bristol's School of Earth Sciences and research leader, said in a statement.

According to the researchers, the huge reservoir of water had been dissolved into partially molten rock at a temperature of almost 1,000 degrees Celsius and could contain a volume of water somewhere between Lake Huron and Lake Superior - some of the world's biggest freshwater lakes. The lake is also characterized by reduced seismic wave speeds and increased electrical conductivity.

"The rock is not fully molten, but partially molten. Only about 10 to 20 percent of the rock is actually liquid; the rest is solid. The rock at these depths is at a temperature of about 970°C," Blundy added.

According to a report by New Scientist, Blundy and his colleagues discovered the lake while investigating the Altiplano-Puna magma body, a huge underground formation that slows down seismic waves and conducts electricity.

The researchers collected the rocks that were ejected from Uturuncu's eruption 500,000 years ago and mixed them with varying amounts of water before exposing them to pressure and temperature conditions similar to those deep in the Earth. They discovered that with a mix of about eight to 10 percent water, the electrical conductivity matched that of the massive anomaly region.

Similar cases have also been discovered, such as those under the Taupo Volcanic Zone in New Zealand and Mount St. Helens in Washington state, which led the researchers to suspect that similar bodies of water could be a common feature under volcanoes. According to Blundy, increased water content in magma could also explain the composition of continental crust rocks.

The researchers aim to understand more about how water could trigger volcanic eruptions and improve predictions of when a volcano is going to erupt.

The findings of the research were published in Earth and Planetary Science Letters.