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The results of the study of the deep structure of the lithosphere in Eastern Siberia are presented. Based on data on the thickness of the permafrost ice horizon, gravity anomalies, geomagnetic field anomalies and seismological data, a model of the structure of the lithosphere of regions with a stable ice horizon thickness was obtained. It is shown that areas with large values of the thickness of the ice horizon gravitate towards the powerful roots of the lithosphere with increased density and magnetization. It has been suggested that the stability of permafrost horizons is provided by cold blocks of the lithosphere roots, which overlap the heat of the mantle. To search for endogenous causes of climatic risks in areas with accelerated degradation of permafrost, deep sections of the earth's crust were built. Analysis of data on the thickness of the ice horizon together with deep sections showed that fluid channels of deep vertical fault zones play a decisive role in the permafrost destruction process. Accelerated degradation of permafrost is localized near the outcrops of fluid-magmatic channels, where specific melting zones have been identified in the form of through taliks caused by endogenous factors of directional action under the influence of fluid flows rising from a depth of ~50–100 km. The studies carried out make it possible to understand the possible causes of the destruction of infrastructure in the permafrost zone and to predict the location of the most probable areas of accelerated degradation.

The results of the study of the influence of the deep factor on the process of melting of the ice cover of the Arctic Ocean and the formation of dangerous natural phenomena are presented. The peculiarities of the structure of the earth’s crust contributing to the ice destruction are visualized based on the interpretation of anomalies of the magnetic field and gravity. Density and magnetic sections of the bottom structures are constructed taking into account seismic and seismological data. Two-dimensional density calculations of the Arctic crust density have been performed to detect fluid-saturated layers. Analysis of satellite observations of ice condition together with interpretation of gravity and magnetic data made it possible to identify natural phenomena of endogenous origin, caused by influence of thermo fluid flows of the earth’s crust. The study of annual and seasonal changes in the thickness of multiyear ice over the period 2007–2020 has shown that a decisive role in the thawing process is played by fluid-supplying channels of deep-seated fault zones. The role of an endogenous factor in the destruction of ice of different ages and in the emergence of dangerous phenomena in the areas of hydrate development has been revealed. This makes it possible to predict the localization of zones of variability in the thickness of multiyear ice, the nature of the destruction of its edges and reduce the risks of navigation.

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