For the first time ever, geologists have used an aerial drone to map the interior of a gigantic blow-out crater, such as those that have appeared with increasing frequency in Siberia.The resulting 3D model, along with other data collected during the study, supports it prevailing theory connecting these bizarre holes in the tundra to increasing heat
“Over the years we have gained a lot of experience with surveillance drones, but this underground aerial survey of the C17 crater was the most difficult task I ever had to perform, on the edge of a ten-story crater and dangling along my path. arms to fly the drone, ”said Igor Bogoyavlensky, a geologist at the Oil and Gas Research Institute of the Russian Academy of Sciences, in a pronunciation
Bogoyavlensky said he nearly lost the drone three times, but he “ managed to get the data for the 3D model, ” details of which are now published in the journal Geosciences.
Andrey Umnikov, a study co-author and director of the Russian Center of Arctic Development, was the first to see C17 which he did from a helicopter in July 2020. The 30 meters deep (30-meters deep) hole is located on the Yamal Peninsula in northwestern Siberia and is located near three other blowout craters, including the Yamal Crater, the sudden appearance of which warned the world to this strange phenomenon back in 2014. Which the researchers are studying opened last summer amid absorb heat
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The current theory behind these craters, which are known to exist, is that they are the result of melting permafrost. Like the A.As the ice heats up, gas, usually methane, accumulates in cavities in the top layer of permafrost. Ultimately, the ground is no longer able to withstand this pressure, giving a mighty farmer in the form of a gas explosion, throwing material away (ejecta) and forming a crater, according to this view. Blow-out holes don’t last very long, as they quickly fill up with water and turn into lakes.
Hence the urgency to organize an expedition to study C17 in detail as soon as possible after its discovery. The team, which was made up of experts from the Skolkovo Institute of Science and Technology, visited the hole in August. 26, 2020 – about 40 days after it was first noticed.
Upon arrival, the team noticed that the hole had widened slightly, the result of further melting and rock collapse. Measurements showed that the depth of the hole was not uniform, ranging from 29 to 33 meters deep.
“The new crater is impressive in its ideal state of preservation, especially the cone-shaped top from which ejecta was thrown, the outer parts of the heaving hill that precipitated the crater, the walls of the crater itself which are incredibly well preserved, and, of course the gas cavity in the ice bottom of the crater, “ Evgeny Chuvilin, a co-author of the study and a scientist at the Skoltech Center for Hydrocarbon Recovery, said
Pieces of ejected material were seen up to 220 meters from the crater, highlighting the force of the explosion.
Importantly, the team arrived in time to find the hole in a “near pristine state” and “with no water filling it,” said study co-author Vasily Bogoyavlensky. At the same time, the icy dome remained largely intact. Prior to the explosion, the cavity contained a circular dome with an elliptical bottom, explained Bogoyavlensky, adding, “From what we know, we can say that the C17 crater is linked to … deep rupture. [tectonics] and an abnormal terrestrial heat flow. ”
Igor Bogoyavlensky piloted the aerial drone, marking the first time a drone was used to investigate an erupting crater. It was also the first opportunity for scientists to study a relatively new crater that had not collapsed or filled with water. (S.cientists have climbed into these things before, but usually only after fill with water. The drone, which was fifteen meters deep, collected valuable data, which allowed the team to build a 3D model of the crater’s interior. The researchers also documented features that were not visible from the surface, such as caves and a suspected cave on the bottom.
According to the 3D model, the crater is approximately 25 meters in diameter, while the gas cavity at the bottom is 13 to 15 meters wide. The gigantic piece of dirty ground ice in the crater is 23 meters thick in some places. The total volume of the underground space is estimated at 353,000 cubic feet (9,910 cubic meters), including approximately 265,000 cubic feet (7,500 cubic meters) of ice.
The team also looked at remote sensing data collected by helicopters and satellites, the latter of which showed the C17 hole sometime between May 15 and June 9 last yearResearch published earlier this month used satellites to even discover more holes in the tundra.
Taken together, these observations reinforce the theory of how these holes form: The steady build-up of gas in an underground cavity creates tremendous pressures, leading to the formation of a “perpetual heaving hill,” or PHM, according to the study. Should the growth of a PHM reach a critical threshold, a volcanic explosion will ensue, forming a large crater.
“The specific shape of the subterranean cavity in the massive ice, the structure of which is depicted by a digital 3D model, is of great importance for the actual confirmation of the cavity model,” the authors wrote in the paper. “It proves the model of its formation in the massive ground ice, the gas dynamics mechanism of the PHM formation and the powerful gas discharge with the destruction of the arc section of the underground cavity and the PHM itself.
Looking ahead, the scientists hope to learn more about the gas and where it comes from, how it accumulates in the cavities, and how this could result in such a powerful explosion. The team expects to revisit blowhole C17 later this year to continue investigating this curious natural phenomenon in a man-made turn.