Exploding tundra in Siberia reveals new clues about permafrost and methane release

The first crater was found in 2014 in the far north of western Siberia, the result of a spontaneous underground explosion that sent earth flying in all directions. More discoveries followed, with some of the holes more than 150 feet deep.

The cause was a mystery at first, but scientists eventually linked the exploding land to climate change and rising temperatures. As the permafrost thaws, they determined, pockets of methane can form below the surface.

But questions remained: Why were the explosions happening only in Siberia, when the Arctic as a whole is warming even faster than the rest of the planet? And will the blasts become more frequent if the planet continues to heat up?

Now, a new study in the journal Science of the Total Environment is offering answers.

Helge Hellevang, an environmental geoscientist at the University of Oslo and lead author on the new study, said he first got interested in the craters, on the Yamal and Gyda peninsulas, after watching a short BBC documentary about them. “We immediately wanted to understand how these could form,” Dr. Hellevang said.

His team examined the literature, he said, but none of the published research on the craters gave a satisfactory explanation of why the craters formed on the two northern peninsulas and not in the “vast areas of permafrost elsewhere in the Arctic.”

So Dr. Hellevang and his colleagues decided to take a closer look at the data. They started with a review of published observations in English and Russian. Based on that review, the team created its own computer models for the origin of the explosions.

This part of Siberia is known for its large deposits of natural gas. But Dr. Hellevang and his colleagues noticed that the Yamal and Gyda peninsulas also had signs of permafrost thinning related to faulting, essentially splits in the underlying rock caused by tectonic activity in the area. He suspected that the faults played a role in the formation of the gas craters.

According to the team’s computer models, the conditions for an explosion start to form when gas moves up through faults into a cavity under the permafrost that’s solid enough to prevent most of the gas from leaking into the atmosphere. When higher temperatures thaw that permafrost, forming shallow lakes at ground level, the seal is weakened.

At the same time, pressure inside the cavity increases as higher temperatures release gas trapped under the ice, which combines with over-pressurized gas coming from faults deep below. If the pressure in the cavity gets too strong, according to the models, the whole thing can go off in a giant blast. And sometimes, it does.

Since that first discovery in 2014, anywhere from eight to at least 17 gas craters, depending on how you define them, have been discovered on the two peninsulas. And the phenomenon could become more common, according to Dr. Hellevang.

“As atmospheric heating and weakening of the surface permafrost continuous, it is likely that more explosions will occur,” he said.

Evgeny Chuvilin, a geologist with the Skolkovo Institute of Science and Technology in Moscow who has studied the gas craters but was not involved in Dr. Hellevang’s work, said the new study brought earlier research together very well. But while the models used are good, Dr. Chuvilin said, the geology of the area is “poorly studied” and nobody has bored deep into the craters to see their full depth.

“The available individual geophysical data are indirect and remain unvalidated,” Dr. Chuvilin said. One limitation of the models proposed by Dr. Hellevang’s team, he said, is that it does not explain how cavities form below the surface in the first place.

It’s possible that such explosions have occurred in the past, but they might have been missed because satellite observations of the area were less frequent and the local population is sparse. Because some debris probably fall back into fill these craters after an explosion, it’s also very likely they were even deeper initially.

“These craters degrade quickly into lakes as they melt or fill with water, so it is possible that we have not noticed all of them forming before they degraded,” said Lauren Schurmeier, a researcher at the University of Hawaii who published a separate study on the gas craters in 2023. “There are many more lake-like structures in this area than craters.”

Dr. Hellevang said he would like to observe how these gas craters begin to evolve into lakes over the years, and whether they begin to look like other lakes in the region. Conditions were similar or warmer in the area about 9,000 to 10,000 years ago, and it’s possible such craters occurred then, as well.

If so, some water bodies may have had a violent beginning. “Many of these lakes could have been emissions craters,” Dr. Hellevang said.

https://www.nytimes.com/2025/09/16/climate/siberia-craters-exploding-permafrost-tundra.html