In 2020, the Yamal Peninsula in Siberia, Russia, is definitely one of the most topical areas in the world, because in 6 years, 17 sinkholes have appeared here. Originally, tiankengs are not uncommon, but tiankengs here are always caused by explosions that blast into the sky. Therefore, all kinds of opinions are raging. Some people say that it is a meteorite hitting the earth, and some people say that it is an underground nuclear explosion test. But after 6 years of investigation, geologist Yevgeny Chuvirin came up with an unexpected answer...
In order to prevent the tiankeng explosion from hurting people, Qiu Weilin monitors the Yamal Peninsula through satellites on the one hand, and encourages citizens to report to him whenever there is an unexplained rise on the ground. In this way, in the following three years, 12 tiankengs were formed successively, some of which took only two months from the ground uplift to the explosion. On December 1, 2017, the satellite also captured the explosion of the "tiankeng" named SeYkhGEC. After the explosion, the flame reached 5 meters, and the combustion lasted 90 minutes before it went out. The explosion also affected a nearby house, and the owner of the house, Moros, was slightly burned. Qiu Weilin visited Morros in the hospital, and listened to him with lingering fears about what happened at the time: "The sound of the explosion was so loud, I was overturned by the air wave, and a fire followed my fingers to my arm..." Doctor Tell Qiu Weilin that Moros' burns were probably caused by methane.
"Methane!" Qiu Weilin thought of the methane detected in the pit last time. "Is the culprit really methane, but where did so much high-concentration methane come from? Besides, the explosion requires considerable thrust. Super high pressure is formed under the surface."
Just when Qiu Weilin decided to follow this line of thought to investigate, a helicopter of Yamal Al Jazeera had an accident. It turned out that the crew of the film crew took a plane to take an aerial shot of the sinkhole, but they encountered an explosion in the sinkhole. The damaged plane was taken A forced landing resulted in two injuries.
Embarrassing truth
The constantly emerging tiankengs and the arduous investigations have reached June 2020. According to Qiu Weilin’s statistics, a total of 17 tiankengs have appeared in the entire Yamal Peninsula. Fortunately, most of these tiankengs are far away from residential areas. Did not cause much casualties.
On July 22, after receiving a report from the citizens, Qiu Weilin and his assistants rushed to Obi Village in the northwest of the Yamal Peninsula again. As soon as he got off the plane, Qiu Weilin felt a heat wave. Diogu, a villager in charge of the reception, complained that the weather this year was really strange. It was only 15°C at this time in previous years, but it reached 25°C this year.
After night fell, Qiu Weilin walked in the coniferous forest, still feeling a trace of warmth. In chatting with Diogu, he told a strange thing. It turned out that his well was dry and needed to be dug. The original plan was to complete it in 15 days, but it was completed in less than 6 days. Qiu Weilin was very curious, and when he asked again, he found that the permafrost layer had become thinner. It used to be 40 meters, but this year it was 10 meters.
How did the frozen soil layer become so thin? Qiu Weilin quickly thought of the hot weather this year: the increase in temperature caused most of the permafrost to melt away. Following this idea, Qiu Weilin sketched out a clear inference: the temperature rise caused the frozen soil to melt, and the humus hidden in the frozen soil began to be decomposed after the frozen soil melted, thereby releasing a large amount of methane, which is in a confined space. The gathering, and finally an explosion due to excessive pressure, forming a tiankeng.
In order to confirm his inference, Qiu Weilin collected hundreds of kilograms of frozen soil and placed it in a sealed plastic bottle, and then placed the bottle in a room temperature environment. Everything was normal for the first few days. After a week, the bottle began to expand. On the tenth day At night, the bottle finally exploded and produced a little spark and black smoke. Qiu Weilin collected the gas composition after the explosion and, as he expected, detected methane.
The culprit of the explosion was methane, but the experiment used a closed space such as a plastic bottle. How did the soil form such a closed space? Just when Qiuweilin was in trouble, Diogu reported to him that a piece of land had been arched 5 kilometers north of the village. Qiu Weilin was overjoyed and hurried over. After investigation, it was indeed the same as the topography of the tiankeng formed before. Qiu Weilin decided that instead of waiting for the tiankeng to explode, he wanted to dig it artificially to release the accumulated methane. His idea was approved by the Russian government, and several excavators were transferred.
For safety reasons, the engineering team first drove an 80-meter-long steel pipe. When the torch was placed on the steel pipe mouth, a flame suddenly appeared. After testing, the main component of the combustion was methane. In this way, after a week of burning, the flames of the steel pipe mouths gradually diminished. With the start of the excavator, Qiu Weilin discovered an interesting phenomenon: a ring-shaped structure around the arch. As the excavation deepened, a cylindrical shape appeared in front of people, and the rock in the cylindrical shape was obviously looser than the surrounding ones. When excavated to a depth of 42 meters, the rocks at the bottom of the tiankeng are no different from the surrounding rocks. At this point, the cause of the tiankeng has finally been solved: due to special geological conditions, the Yamal Peninsula has formed many such special cylindrical terrains. Because the cylindrical geological structure is looser than the surrounding rocks, the temperature rise caused the humus of the frozen soil to decompose and release methane. And gathered, and eventually the pressure was too strong to break through the surface of the soil, causing an explosion to form a cylindrical tiankeng.
In September 2020, Qiu Weilin announced the findings: “As a potent greenhouse gas, methane leaking from permafrost may accelerate global warming, leading to more permafrost melting. But in Asia On the Marl Peninsula, the giant hole may trigger another process, and this process will add more uncertainty to the complex feedback loop between temperature rise, permafrost melting and greenhouse gas release. If eventually found, trapped underground The methane deposits in the deep permafrost began to seep upward from the normally impenetrable permafrost, which may indicate that the ice cap above the tundra will become more permeable. Changes in the Arctic may have a wider impact on global warming This may bring new uncertainties."
The cause of the tiankeng has not been unanimously recognized by geologists, but the reason for the explosion of underground gas accumulation has led them to reach a consensus, that is, climate warming. In recent years, the temperature rise in the Arctic has been twice the global average temperature rise. Every summer, the frozen soil layer in this area is melting rapidly. The many organic matter under the frozen soil layer releases a large amount of gas under the increasing temperature. The methane in the frozen soil layer is even more amazing. Speed is released.
Qiu Weilin said with concern: "There is no place in the world like this, because climate warming has caused such drastic changes in the geomorphic structure." And the impact of climate warming on the region is far more than that. You must know that the Arctic The carbon content in the circle is twice as much as that in the atmosphere, and continued warming will continue to intensify the greenhouse effect. In Qiu Weilin's view, the successive occurrence of sinkholes is an alarming warning: "It reminds us that the impact of climate warming has become more and more important to not be ignored."
Kudria’s analysis has been recognized by many people, but Qiu Weilin knows that such a tiankeng requires at least six conditions: one is that the limestone layer must be thick, and only thick enough rock layers can provide enough for the formation of tiankeng. Space; the second is that the water level of the underground river must be deep enough; the thickness of the three-packed gas zone, that is, the gas-bearing rock layer, must also be large; fourth, the rainfall in the area must be large, so that the flow and power of the underground river should be large enough to reduce The falling stones wash away; the fifth condition is that the rock formations should be level. From the cliffs around the tiankeng, the rock formations are basically parallel to the ground, just like layers of slabs piled around. There is only such a rock formation. In order to collapse; the last point is that the crust must be uplifted, so that the movement of the crust will provide impetus for the collapse of the rock. But after this period of investigation, Qiu Weilin found that the Yamal Peninsula obviously does not have such geological conditions.
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