Non-Destructive Approach For Studying Medieval Settlements Destroyed By Ploughing: Combining Aerial Photography, Geophysical And Soil Surveys

The procedure for studying medieval settlements destroyed by ploughing is applied to one of the largest Finno-Ugric ancient settlement sites of western Urals, Guryakar (ninth-thirteenth centuries ad). The approach implies the consistent use of a number of mutually confirming non-destructive methods of survey: aerial photography using unmanned aerial vehicles followed by geophysical and soil surveying. Aerial photography in the visible spectrum enables the evaluation of possible settlement boundaries. The wavelet transmission of multispectral aerial photography data makes it possible to disclose the areas of the preserved cultural layer. A set of geophysical methods (resistivity survey, magnetic survey and electrical resistivity tomography) is used to verify and analyse these data. Additionally, geophysics makes it possible to identify fortifications and diverse layout objects that are not expressed by the surface topography. Follow-up soil drilling is a way to verify the proposed reconstruction of the layout, and the study of the chemical properties of soil cores makes it possible to justify the boundaries of the residential and industrial areas of the settlement. For this purpose, in the final stage, statistical processing of the chemical properties of soil materials is carried out (principal component analysis and the k-means algorithm classification). This approach complements the comparative analysis of diverse data and significantly increases the reliability of historical reconstruction.Interdisciplinary studies conducted at the medieval Finno-Ugric settlement of ancient Guryakar allowed fundamentally new information to be obtained for use in historical reconstructions: this work revealed a previously unknown line of the layered fortification system, reconstructed the layout of all four structural parts of the settlement and justified diverse building areas.