Siberia's mysterious craters linked to methane thaw blasts
Since 2014, mysterious craters have been appearing in the north-western region of Siberia. These new holes in the ground are causing a significant stir, and researchers are trying to understand the mechanism behind their formation. An intriguing hypothesis has emerged.
Mysterious craters have been appearing in north-western Siberia since 2014. According to repost the most recent one, which was formed in August of this year. The issue has captured the attention of scientists trying to explain the mechanism behind their formation. One hypothesis links the craters to natural gas deposits. Another suggests that the craters form after methane explosions are triggered by permafrost thawing.
After studying the craters, a team from the University of Cambridge and the University of Granada reached a slightly different conclusion. "There are very, very specific conditions that allow this phenomenon to occur," explains Ana Morgado, a chemical engineer from the University of Cambridge and one of the study's authors, as quoted by "Advancing Earth and Space Science. "We are talking about a very niche geological space," she added.
In their quest to solve the mystery, scientists considered whether chemical or physical processes caused the explosions. As explained by Julyan Cartwright, a geophysicist with the Spanish National Research Council and a participant in the study, there are only "two ways to trigger an explosion". "Either a chemical reaction occurs, resulting in an explosion like a dynamite blast, or you pump up a bicycle tyre until it explodes — that's physics," indicated the scientist.
According to scientists, the mere thawing of permafrost is insufficient to cause an explosion, although this process is hugely significant. Researchers have focused on cryopegs, pockets of cold brines, which might be closely related to the formation of craters in Siberia.
Underneath cryopegs lies a layer of crystallised methane hydrates (methane clathrate, methane hydrate). These are kept stable by the high pressure and low temperatures inside these cold brine pockets. The situation changes when water from thawing permafrost starts seeping into the brines.
This may lead to the formation of craters in Siberia
In brief, the entire process resembles a balloon bursting when too much gas fills it. The increasing pressure inside the cryopegs creates fissures in the soil, which travel upwards from the cryopeg towards the surface.
The cracked soil then causes a sudden drop in pressure at depth. This change damages the methane hydrates below the cryopeg, causing methane to revert to a gaseous state and leading to a physical explosion.
According to scientists, this process is spread over decades, which means we don't observe these phenomena very often. At the same time, scientists warn that "the amount of methane released may have quite a significant impact on global warming".
