MT/MV methods аномалії електропровідності 3D geoelectric model conductivity anomalies electrical conductivity anomalies magnetotelluric sounding magnetovariational profiling Ukrainian Shield deep structure experimental electromagnetic studies - 3D geoelectrical model 3D геоелектрична модель 3D геоэлектрическая модель Brusyliv fault zone Golovanivsky suture zone Iсторiя науки Kerch iron ore basi Kirovograd electroconductivity anomaly Southern side of the Dnieper-Donets Basin Zvizdal-Zaliska fault zone absorption spectra anomalies of conductivity anomalies of electrical conductivity anomalies of electro-conductivity anomalies of electroconductivity atomic-force-microscopy morphology collision crust deep and audiomagnetotelluric sounding