Seyakha catastrophic blowout and explosion of gas from the permafrost in the Arctic, Yamal Peninsula

For the first time, in a channel of the Arctic river, on the Yamal Peninsula, a pingo-like feature (PLF) was revealed, where, as a result of powerful blowout, self-ignition and explosion of gas on the 28th of June 2017, the giant Seyakha Crater (C11) was formed. Expeditions in 2017, 2018 and 2019 on the C11 Crater and analysis of remote sensing data allowed to reconstruct geodynamical processes of rapid (approximately 3.5 years) growth of the PLF, caused by high gas pressure, and active thermoabrasive processes in summer seasons (speed up to 1.6 m per day), destroying the C11 Crater walls. It was discovered that before the explosion, a gas-filled thermokarst chamber (ice cavity) had existed in permafrost. Based on the use of the ground penetrating radar survey, a model of the crater and the structure of near-surface deposits was created. A previously unknown rise in the base of ground ice, probably connected with gas-dynamic process, was revealed. A scheme of distribution of frozen soil and ground ice fragments, ejected from the crater, was created and analyzed, their maximum distance from the explosion epicenter was defined as 380 m. Long-term gas emission from the crater was observed, which allowed to make a conclusion about volcanic mechanism of eruption. Large distances from deep wells to the location of the explosion (15 km and more) and determined microbial genesis of gas indicate high probability of natural origin of gas blowout and formation of the C11 Crater. •A pingo-like feature was destroyed by a powerful blowout, self-ignition and explosion of gas with formation of a crater.•Short-term gas-dynamical mechanism was proposed for the formation of the pingo-like feature with the gas-filled chamber.•Volcanic type of the eruption was proposed for the Seyakha C11 Crater.