Results of Geophysical Investigations to Study Subaeral Supra Permafrost Taliks in the Area of the Shestakovka River, Central Yakutia

Complex geophysical investigations to study subaerial taliks and permafrost in the experimental area of Left Shestakovka basin (Central Yakutia) were carried out in Autumn of 2023. They included GPR research and CDP sounding, as well as electrical prospecting. It was founded that the depth of the talik on the right flank of the river is range from 2 to 14 meters, with an average depth of 6.1 m. Its depth on the left flank of the river varies from 3 to 7.1 meters, with an average value of 4.2 m. The electrical survey was indicated that the near-surface layer is characterized by resistivity variations from 590 to 4459 Ω·m. Its thickness is about 2 m. The next layer with a thickness of 3 - 5.5 m, has resistivity from 100 to 267 Ω·m, and can be associated with talik. The third layer is determined by increasing the resistivity to 2049 Ω·m, which is typical for permafrost. The lowest layer is characterized by decreasing the resistivity to values of about 221 Ω·m. This is can be associated with lithological composition or with groundwater.