New data on intensive Earth degassing in the Arctic in the north of Western Siberia: thermokarst lakes with gas blowout craters and mud volcanoes

In the last decade, in the north of Western Siberia, the authors carried out a large amount of comprehensive research, which made it possible to obtain fundamentally new information about the gas-dynamic mechanisms of dangerous processes in the Arctic permafrost. According to remote sensing data, at the bottom of thermokarst lakes, rivers and coastal zones of the Kara Sea, more than 4.5 thousand zones of powerful gas blowouts with the formation of craters (pockmark) were found. There are reasons to believe that powerful gas emissions mainly come from shallow deposits with ultrahigh (superlithostatic) pressures. For the first time, large mud volcanic uplifts with pronounced craters have been found at the bottom of the Arctic thermokarst lakes. Based on the monitoring of the ice situation and the water environment on the basis of retrospective satellite images on lakes Otkrytie, Labvarto and Yambuto, the presence of periodic emissions of formation fluids, including gas, is shown. Based on the combination of a number of features, the discovered objects can be classified as active mud volcanoes with a high level of probability. The results of the studies allow us to state that mud volcanism is widespread in the Circum-Arctic megaregion.