New research suggests that the geological conditions of the region, combined with the effects of climate change, have led to the emergence of a series of giant “sinkholes” in Siberia over the past decade.
In 2014, a massive sinkhole appeared on the Yamal Peninsula in Siberia. The sudden appearance of this “sinkhole” and the surrounding materials indicated that an explosion had occurred.
Subsequently, scientists and local residents discovered more than a dozen similar giant “sinkholes” in the area, some of which are as deep as 50 meters.
Scientists survey the giant sinkhole that appeared on the Yamal Peninsula, Siberia in August 2020 – (Photo: Evgeny Chuvilin).
During the investigation, scientists discovered unusually high concentrations of methane around the sinkhole, leading them to believe that a large amount of methane released was responsible for the formation of these holes.
However, new research conducted by chemical engineer Ana Morgado (from the University of Cambridge) and her colleagues argues that the hypothesis of melting permafrost is insufficient to explain the formation of the sinkholes.
Instead, they believe that a series of special conditions related to the region’s unusual geology and the impacts of climate change initiated a process that led to the release of methane through explosions.
According to the study, the warming of the surface soil has resulted in rapid pressure changes deep underground, ultimately leading to the extremely powerful release of methane. The authors noted that the methane release process stems from a physical reaction.
To illustrate, the team compared it to a pump and a bicycle tire. If overinflated, the tire will burst. In the case of Siberia, the pump is the permeability – the process of fluid movement to balance the concentration of dissolved substances within them.
According to IFLScience on October 1, the Yamal Peninsula has layers of permafrost clay acting as a barrier to permeability. Beneath this layer, in some areas of the Yamal Peninsula, there is a layer of unfrozen saline water known as cryopeg. Below the cryopeg are layers of water-methane hydrates that are maintained in a stable state due to low temperatures and high pressures.
However, climate change has allowed water from melting ice to permeate down, leading to pressure changes and causing cracks to form. These cracks expand, resulting in sudden pressure drops deep underground, breaking the structure of the methane hydrates beneath the cryopeg and releasing methane gas through an explosion.
The research team concluded that the process leading to the aforementioned methane-releasing explosions takes decades to occur, consistent with the rising climate temperatures since the 1980s.
The study was published in the journal Geophysical Research Letters.
