Giant Crater in Siberia May Have Exploded From Climate Change-Induced Cryovolcanism

A colossal crater that opened up on Siberia's Arctic tundra may have formed through a huge explosion resulting from climate change-induced cryovolcanism, a scientist studying these formations has said.

The crater, which is 164 feet deep, was discovered by a film crew that was flying over the Yamal peninsula on an unrelated assignment. Following the find, the site was visited by scientists who are now studying the crater to understand how it was formed.

The presence of these enormous craters came into focus in 2014 when a 130-foot-wide crater was found in this remote region. After studying the site, scientists came to the conclusion it likely formed through an enormous explosion caused by the build-up of methane beneath—a process known as cryovolcanism.

Deep beneath the ground, there are pockets of unfrozen ground called cryopegs. Methane gets trapped within these pockets and pressure starts to build. When the permafrost above starts to thaw, the ground becomes unstable and weakens, resulting in huge blowouts. As the climate warms, permafrost across the Arctic is becoming increasingly unstable. It is thought this instability may be the reason scientists are now seeing more of these craters open up.

How many craters like this exist and how often they form is not known, owing to the remote locations they tend to be found in. Before they explode, it is thought the ground swells up. In 2017 over 700 sites where this "swelling" was taking place had been identified, according to the Siberian Times. Previous footage also released by the newspaper showed the ground wobbling underfoot, which was thought to be the result of a methane buildup.

Evgeny Chuvilin, lead research scientist at Russia's Skoltech Center for Hydrocarbon Recovery, has spent two years studying a 65-foot-wide crater in Yamal. He has now visited the newly found crater to investigate how it formed.

"As of now, there is no exhaustive theory for the formation of these craters," he told Newsweek in an email. "The explosive events behind them are too rare and too hard to catch in the act to study properly: a fresh crater usually 'lives' for just one to two years, and these are remote areas with little observation, although that has been changing due to remote sensing and exploration of Yamal."

In their latest research, Chuvilin and colleagues propose the crater they studied "matured" in a lake left over from an ancient channel within the Erkuta–Yakha River. He said the lake had a zone of unfrozen solids known as a 'talik' that started to re-freeze. Gasses started to accumulate in this freezing talik, causing stress to build that was ultimately released as a powerful explosion.

"It is possible that the new crater followed that same model," he said. "But we have yet to study this and evaluate the role of deep processes and ascending gas-water fluids in the formation of this crater, including the formation of a gas cavity. Climate change might also be one factor in these cryovolcanic processes, as excessive warming in the top permafrost layer can arguably contribute to these explosions. But this is still something that requires a lot of careful research."

Susan Natali, Arctic Program Director at the Woodwell Climate Research Center in Massachusetts, said that while she had never seen a crater forming, the explosion would be "very, very powerful."

"Some have caused localized fires at the point of explosion and all emit massive quantities of soil and ice from the depth of the crater to the surrounding tundra," she told Newsweek via email. She said the problem with studying these craters is finding them in remote locations, and that they soon fill with water and end up looking just like one of the thousands of lakes dotted across the landscape. Natali and her team are currently mapping potential craters with satellite data and have found several candidates they plan to explore further.

"I think there will be a lot more to learn about crater formation and distribution once more are identified," she said. "What we do know is that these craters represent a new process in Earth System Science that was unknown and unexpected before they were first discovered. I think they are a good indicator of the rapid changes that are underway in the Arctic and provide a framework for understanding the potential for abrupt climate-mediated changes in the Arctic and globally."