Over ten years following the initial observation of enigmatic depressions within Siberia’s permafrost, researchers continue to propose novel hypotheses—ranging from gaseous detonations to celestial impacts—regarding their genesis.

A collective of geoscientists affiliated with the University of Oslo, under the guidance of Helge Hellevang, has now contributed a fresh theoretical framework. This proposal aims to elucidate why these geological features have manifested exclusively on the Yamal and Gydan peninsulas, rather than appearing in other permafrost environments across the Arctic.

The inaugural occurrence was documented in Siberia’s Yamal region in 2014. This particular formation measured approximately 30 meters (98.4 feet) in diameter and exceeded 50 meters in depth, with surrounding ejecta indicative of an explosive origin. These perplexing voids exhibit such remarkably sheer walls that one might easily assume their excavation was a result of mechanical effort.

Hellevang and his associates concur that an accumulation of pressurized methane serves as the principal catalyst for these formations, now cataloged as gas emission craters (GECs). However, whereas previous hypotheses posited that the specific characteristics of the permafrost itself were solely responsible for initiating these craters, the current investigation suggests this notion is improbable.

“Should internal permafrost processes, stimulated by climatic shifts, have been the cause of these expulsions, one would anticipate GECs to manifest in other permafrost zones harboring gas hydrates, ground ice, or cryopegs. This is demonstrably not the situation,” the researchers asserted.

“The sheer volume of gas-filled voids necessary to account for the GEC formation and associated ejecta is unlikely to develop solely through internal permafrost mechanisms.”

diagram showing four stages of GEC formation. 1 weakening of permafrost from increased lake density, some along fault lines. 2 thinning of permafrost and collapse, GEC formation, ejecta released tens to hundreds of meters. 3 GEC as first observed. 4 GEC fills with water and debris, peatification insulates crater leading to back-freezing. crater is disguised as normal thermocarst feature.
A conceptual model depicting the four phases of GEC genesis, commencing with alterations and thinning of the permafrost layer, and concluding with a post-closure stage that obscures the previously formed GEC. (Hellevang et al., Sci. of the Total Env., 2025)

Conversely, their findings indicate that thermal energy and natural gas originating from substantial depths beneath the permafrost—specifically, emissions from subsurface fault systems prevalent in the Yamal and Gydan peninsulas—would be requisite to generate the substantial force for such subterranean expulsions. This aligns with the geological context, given that these peninsulas are situated atop one of the planet’s most significant deposits of natural gas reserves.

A) A probabilistic map illustrating Arctic permafrost distribution (adapted from Obu et al., 2019); B) Seven identified GECs (represented by yellow circles) and associated gas/oil fields on the Yamal and Gydan peninsulas; C) and D) depict GECs C1 and C2 respectively. (Hellevang et al., Sci. of the Total Env., 2025)

Their perspective still acknowledges a role for climate change, suggesting it might be the factor enabling the full exposure of these formations. This occurs as expanding bodies of water compromise the permafrost’s integrity, creating a considerably attenuated ‘cap’ through which gas can forcefully erupt.

While this proposed model offers a robust explanation for the origin of these craters, its validity requires rigorous testing against empirical field data. Only then may we achieve a comprehensive understanding of the subterranean processes driving these remarkable geological phenomena.