This article describes the results of an Arctic expedition studying the new giant gas blowout crater in the north of Western Siberia, in the central part of the Yamal Peninsula in 2020. It was named C17 in the geoinformation system “Arctic and the World Ocean” created by the Oil and Gas Research Institute of the Russian Academy of Sciences (OGRI RAS). On the basis of remote sensing, it can be seen that the formation of the crater C17 was preceded by a long-term growth of the perennial heaving mound (PHM) on the surface of the third marine terrace. Based on the interpretation of satellite images, it was substantiated that the crater C17 was formed in the period 15 May–9 June 2020. For the first time, as a result of aerial photography from inside the crater with a UAV, a 3D model of the crater and a giant cavity in the ground ice, formed during its thawing from below, was built. The accumulation of gas, the pressure rise and the development of gas-dynamic processes in the cavity led to the growth of the PHM, and the explosion and formation of the crater.

Gas hydrates (GH) are perspective energy sources, containing significantly more gas resources compared with conventional fields. At the same time, GH pose a danger for exploration and production of hydrocarbon fields. Methane release to the atmosphere is also a substantial factor of climate change. The objective of this research was the forecast of distribution of zones, favorable for GH existence in the Arctic Ocean and adjacent offshore areas, limited by the 45° latitude. For conducting research, existent data of National Oceanic and Atmospheric Administration (NOAA) on near-bottom water temperatures was analyzed. Using CSMHYD software, based on empirical equations of GH stability, minimal depths appropriate for methane hydrates formation at different temperatures were calculated. On the basis of obtained values, a cartographic scheme with a zone favorable for methane hydrates existence was created. The zone corresponded to distribution of BSRs defined in seismic sections, including those discovered for the first time on the continental slope of the Laptev Sea and in the TINRO Depression of the Sea of Okhotsk. Besides, the zone concurred with the results of other authors research, summarized in the geoinformation system “AWO” (The Arctic and the World Ocean), which could verify the validity of conducted forecast.

This article describes the main results of two Arctic expeditions in 2017–2018 to study the Seyakha Crater in the north of Western Siberia, Yamal Peninsula. It was formed on a place of a pingo-like feature (PLF) by huge blowout, self-ignition, and explosion of gas on 28 June 2017. In 2018, for the first time, the integration of geophysical studies on the Yamal Peninsula revealed in detail an Arctic gas-blowout crater within a river channel and adjacent land with permafrost. On the basis of unmanned aerial vehicle photography, echo sounding, and ground penetrating radar survey data processing, a 3D digital elevation model (DEM) of the crater and the structure of near-surface deposits was created. A previously unknown uplift inside the permafrost layers, probably connected with the processes of gas chamber formation, was revealed. A long period of continuous gas emission (mainly, biogenic methane) from the Seyakha C11 Crater (2017–2019) and other existing data show evidence for a gas-dynamic mechanism of the PLF growth and a volcanic type of eruption.

The purpose of this work was to analyze the causes of intensive gas emission in the central part of the Laptev Sea. On the basis of a seismic survey of the JSC Marine Arctic Geological Expedition, the wave fields have been studied on 28 profiles with a total length of 5930 km. Zones with refracted waves from the high-velocity horizons, associated with frozen sediments and possible occurrence of gas hydrates, have been revealed. For the first time for the region, a cartographic scheme of change in the refracted wave propagation velocity and physical state of bottom sediments (frozen or thaw) has been created. The absence of permafrost and gas hydrates in the area of active gas emission was proved, and the deep origin of gas and its migration along tectonic faults were grounded.

The article is devoted to the four-year (2017–2020) monitoring of gas emissions from the bottom of the Seyakha Crater, located in the central part of the Yamal Peninsula (north of Western Siberia). The crater was formed on 28 June 2017 due to a powerful blowout, self-ignition and explosion of gas (mainly methane) at the site of a heaving mound in the river channel. On the basis of a comprehensive analysis of expeditionary geological and geophysical data (a set of geophysical equipment, including echo sounders and GPR was used) and remote sensing data (from space and with the use of UAVs), the continuing nature of the gas emissions from the bottom of the crater was proven. It was revealed that the area of gas seeps in 2019 and 2020 increased by about 10 times compared to 2017 and 2018. Gas in the cryolithosphere of the Arctic exists in free and hydrated states, has a predominantly methane composition, whereas this methane is of a biochemical, thermogenic and/or mixed type. It was concluded that the cryolithosphere of Yamal has a high level of gas saturation and is an almost inexhaustible unconventional source of energy resources for the serving of local needs.

As a result of five-year studies of approximately 1.3 mln sq km of the East Siberian Arctic Shelf, a boundary between areas with predominant distribution of frozen and thawed ground (Southern and Northern zones) was revealed, new information was obtained on the state of subsea frozen ground, cardinally different from all previous data. For the first time, it was established that in most part of the East Siberian shelf (57.6%, 737 thousand sq km), frozen ground completely degraded, which also reduced the area of possible gas hydrate existence. Frozen ground degraded most intensively on the shelf of the East Siberian Sea (76.9%, 665 thousand sq km). The results were obtained based on seismic records of refracted waves for 176 seismic lines of JSC MAGE and JSC RosGeo with total length of more than 34 thousand km. The correctness of the results is approved by data of drilling of a number of wells, including those of PJSC NK Rosneft. The results have great significance for the forecast of climate changes and increasing efficiency of hydrocarbon resources exploration and development.