Application of Electrical Resistivity Tomography (ERT)in the investigation of quaternary landslide zones, based on the selected regions of Płock slope

The article shows the results of geophysical surveys performed by using Electrical Resistivity Tomography (ERT) method on selected ragion of Płock slope of a Tumski hill near Basilica of Assumption of the Blessed Virgin Mary in Płock and in Maszewo by the Vistula River a few kilometers north of Płock. The above-mentioned sections were selected due to landslide phenomena observed there. Geophysical surveys were conducted in order to verify the state of the distribution of electrical resistivity in the sectors where mass movement was identified. The electrofusion crosssection near Cathedral Basilica shows clays and sands. Also in ERT prospection a zone of loose soils with high resistance is clearly visible. The results of the ERT method from Maszewo, indicates historical land surface of a landslide and that the slope in Maszewo consists of cohesive deposits. In order to describe these particular issues, geological cross-sections and safety factor obtained by calculation are presented for the analyzed parts of the slope. The safety factor shows that probability of landslide activity near Cathedral Basilica is very unlikely and in Maszewo is very high.