Przydatność pomiarów georadarowych i analiz geomorfometrycznych do rozpoznania wewnętrznej struktury płytkich osuwisk – na przykładzie góry Średniak w Masywie Śnieżnika, Sudety Wschodnie

Abstract

Evaluation of usefulness of integrated ground-penetrating radar and geomorphometric analyses applied to recognition of internal structure of shallow landslides – case study from Mt. Średniak in the Śnieżnik Massif, Eastern Sudetes.A b s t r a c t. The paper reviews an application of non-destructive electromagnetic imaging of shallow bedrock and landslide colluvium horizons performed with ground-penetrating radar (GPR) technique on mass movement-affected mountain slope. We used a non-shielded 52 MHz GPR equipment to study an area of a shallow translational landslide, which developed on steeply inclined gneissic bedrock on Mt. OEredniak slopes (1210 m a.s.l.) in the Śnieżnik Massif. This landslide originated at the boundary zone between intact bedrock comprising Proterozoic gneisses and uppermost slope cover, as a result of continuous rainfall during July of 2011. Furthermore, to better understand and examine a landslide area on Mt. Średniak slopes we also applied structural geological and geomorphological methods. The GPR analyses resulted in high-resolution imaging of internal slope structure and gravitational deposit architecture in the range of 0.5–5 m below surface level. Electromagnetic sounding performed directly above the landslide source area elucidated a set of bedrock discontinuities with a possible direct impact on water aggregation and migration during the rainfall episodes. Furthermore, a GPR profile performed in a landslide toe area, showed subsurface reflection horizons to be correlated with a colluvium/bedrock transitional zone and internal heterogeneous architecture of colluvial deposits. Ground-penetrating radar proved to be both powerful and an easy-maintained 'on-site' method for steep mountain slope analysis, with a potential for high-resolution imaging of shallow-seated gravitational slope deformations.