Geoelectrical Survey of Active Layer Depth in Urban and Mature Environments of Yamal Region

Abstract

Active layer thickness and the depth of the permafrost are the basic features of the soil cover of the Arctic region. Urban ecosystems are characterized by disjunctive character of soil cover. Identification of separate soil bodies within the urban ecosystems, their spatial limitation and vertical stratification should be performed for adequate ecological assessment of urban territories. Methods of field electrophysics, which do not lead to any mechanical disturbances of soil cover, should be preferably used for both urban and natural environments. Studied soil profiles revealed significant differences in profile distribution of electrical resistivity values and active layer depths. Predominance of sand fraction in soil of Salekhard site (Spodic Cryosol) determines higher rates of thawing process compared to soil from natural site (Aquiturbic Cryosol), where clay is predominant fraction. Both soil profiles and their electrical resistivity curves are significantly affected by natural cryoturbation processes. However, vertical profile of electrical resistivity value in urban soil is more complicated and has a number of fluctuations due to higher rates of ground mixing, mechanical pressure and high amount of artefacts.