CAPABILITIES OF PASSIVE SEISMIC METHODS FOR STUDYING THE GEOLOGY OF ARCTIC REGIONS IN WESTERN SIBERIA ( <i>Yamal Peninsula</i> )

This paper provides a brief review of methods based on the analysis of natural microseismic ground vibrations – collectively known as passive seismic methods. These include spatial autocorrelation, seismic interferometry, and the spectral ratios of seismic noise components. Their application for studying the structure and properties of the shallow subsurface in the Arctic is discussed. The shallow section across frost mounds in the Arctic is analyzed and interpreted using the spectral ratios of seismic noise components. The resulting two-dimensional sections reveal a horizontally bedded structure, with four main beds distinctly identifiable on the profiles. These beds are interpreted as an upper sedimentary bed, a basement, and two intermediate beds distinguished by their velocity characteristics. The section is disrupted by vertical and inclined heterogeneities that extend from the basement faults to the surface, exhibiting high anisotropy and reduced rigidity. The spatial correlation between these subvertical heterogeneities and the surface locations of frost mounds suggests that these areas represent zones of weakness, possibly fault zones or fluid migration pathways. A review of scientific publications suggests that the results obtained using passive seismic methods are reliable, as also confirmed by other independent geophysical techniques. Passive seismic methods prove highly effective in hard-to-reach areas like the Arctic because they do not require long-term deployment of an observation network. Furthermore, spectral ratio methods do not necessitate a large number of seismic stations. These methods are particularly useful for studying hard-to-recover hydrocarbon reserves characterized by a complex shallow structure (several meters). They enable rapid investigation of the upper section at depths ranging from a few meters to tens of kilometers during reconnaissance work, with minimal financial and labor investment. From an environmental standpoint, passive seismic methods are the least intrusive, as they are non-invasive and non-destructive.