The cause of a series of giant explosion craters in Siberia

The sudden appearance and material surrounding the hole suggest it was formed by an explosion. Since then, scientists and local people have discovered many more holes. These holes are huge, some up to 50 meters deep, and release methane gas.

According to new research published in the journal Geophysical Research Lettersthe authors suggest that a series of conditions due to the area’s unusual geology and climate change triggered the release of methane, leading to an explosion, IFL Science reported on October 1. Ana Morgado, a chemical engineer at the University of Cambridge, and colleagues suggest that surface warming leads to rapid pressure changes deep underground, causing a violent release of methane gas.

“There are only two ways to create an explosion. Either a chemical reaction occurs and you get an explosion like when dynamite explodes, or you pump up a bicycle tire until it explodes – that’s physics.” , said Julyan Cartwright, a geophysicist at the Spanish National Research Council.

The Siberian craters have no trace of a chemical reaction, meaning they formed from physical causes. The “pump” in this case is osmosis – the process by which liquid moves to equalize the concentration of solutes in it.

The Yamal Peninsula has a thick layer of clay-like permafrost that normally acts as a permeability barrier, but climate change has changed this. Permafrost, 180 – 300 m thick, lies below a layer of topsoil called the “active layer”. While permafrost is always frozen, topsoil melts and refreezes seasonally.

In the permafrost layer in some places on the peninsula there are special layers of unfrozen water with high salinity, called cryopeg. They remain in a liquid state thanks to pressure and salinity. Below the cryopeg is a layer of methane solids – water of crystallization called methane hydrate, which should be stable due to low temperatures and high pressures.

But now, as the average temperature increases, the active layer is melting and expanding downward until it reaches the cryopeg layer due to osmotic pressure. Since there is not enough space in this layer to accommodate additional melt water, the pressure begins to increase. The pressure causes cracks to appear and gradually run to the surface, leading to a sudden pressure drop at great depth. That sudden change in pressure damages the methane hydrate below the cryopeg, leading to the release of methane gas and causing a physical explosion.

The team concluded that the process leading to these explosions could take decades, consistent with the increase in global temperatures since the 1980s. “This may be a rare phenomenon. But the amount of methane released can have a big impact on global warming,” Morgado said.