For the first time, geologists have used an aerial drone to map the interior of a giant explosive crater, which have appeared regularly growing in Siberia.. The resulting 3D model, along with other data collected during the survey, reinforces the file dominant theory linking these strange holes to the tundra to increase the heat.
“Over the years we have gained a lot of experience with surveillance drones, although this underground aerial study of the C17 crater was the most difficult task I had ever faced, having to be lying on the edge of a crater 10-story deep and hang up your arms to control the drone, “said Igor Bogoyavlensky, a geologist at the Oil and Gas Research Institute of the Russian Academy of Sciences. statement.
Bogoyavlensky said he was about to lose the drone on three occasions, but “managed to get the 3D model data,” the details of which have now been published in the journal Geosciences.
Andrey Umnikov, co-author of the study and director of the Russian Arctic Development Center, was the first to detect C17 which he did from a helicopter in July 2020. The depth of 98 feet (30-meters deep) is located on the Yamal Peninsula in northwestern Siberia, and is located near three explosion craters, including Yamal Crater, whose sudden appearance alerted the world to this strange phenomenon in 2014. What researchers study open this past summer in the middle heat record.
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The current theory of these craters, of which 20 are known to exist, is that they are the result of permafrost melting. Like thethe Arctic heats up, the gas, mainly methane, accumulates inside cavities located in the upper layer of the permafrost. Finally, the ground can no longer contain this pressure and produces a powerful belching in the form of a gas explosion, throwing material (ejectes) and forming a crater, according to this view. Explosion holes do not last long, as they quickly fill with water and turn into lakes.
Hence the urgency of organizing an expedition to study C17 in detail and to do so as soon as possible after its discovery. The team, which included experts from the Skolkovo Institute of Science and Technology, visited the hole in August. 26 of 2020: approximately 40 days after the first vision.
Upon arrival, the team noticed that the hole had increased slightly in size as a result of the melting and collapse of the rock. 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, mainly the cone-shaped top from where the ejections were thrown, the outer parts of the lifting mound that precipitated the crater, the walls of the crater itself that are incredibly well preserved and of course the gas cavity at the icy bottom of the crater “ Evgeny Chuvilin, co-author of the study and scientist at the Skoltech Center for Hydrocarbon Recovery, said.
Pieces of material ejected 220 meters from the crater were seen, highlighting the force of the explosion.
It is important to note that the team arrived in time to find the hole in an “almost virgin state” and “without water to fill 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, Bogoyavlensky explained, adding: “From what we know we can say that the C17 crater is bound to … deep fault [tectonics] and an abnormal terrestrial heat flow “.
Igor Bogoyavlensky flew the aerial drone, marking the first time a drone was used to inspect an explosion crater. It was also the first opportunity for scientists to study a relatively new crater that had not collapsed or filled with water. (Sscientists have rose within these things before, but only after mostly filling with water.) The drone, which reached 15 meters deep, collected valuable data, which allowed the team to build a 3D model of the interior of the crater. The researchers also documented features not visible from the surface, such as caves and an alleged cavern at the bottom.
According to the 3D model, the crater has a diameter of about 25 meters, while the gas cavity at the bottom measures between 13 and 15 meters wide. The giant piece of dirty earth ice in the crater it measures 23 meters thick in some places. The total volume of underground space is estimated at 353,000 cubic feet (9,910) cubic meters), including about 7,500 cubic meters of ice.
The team also examined remote sensing data collected by helicopters and satellites, which showed that hole C17 formed sometime between May 15 and June 9 last year. Research published earlier this month he used satellites to even discover more holes in the tundra as well.
Taken together, these observations reinforce the theory on how these holes are created: the constant accumulation of gas inside an underground cavity leads to enormous pressures, which lead to the formation of a “perennial mound,” according to the study. If the growth of a PHM reaches a critical threshold, a volcanic-type explosion occurs that forms a large crater.
“The specific shape of the underground cavity in the massive ice, the structure of which is represented by a digital 3D model, is of great importance for the factual confirmation of the cavity formation model,” the authors wrote in the paper . “It demonstrates the model of its formation in the massive terrestrial ice, the gas-dynamic mechanism of the formation of PHM and the powerful explosion of gas with the destruction of the part of the arc of the underground cavity and the same PHM.”
Looking to the future, scientists hope to learn more about the gas and where it comes from, how it accumulates inside cavities and how this can cause such a powerful explosion. The team hopes to revisit the C17 blower later this year to continue investigating this curious natural phenomenon with a human-induced twist.