Origin of block accumulations based on the near-surface geophysics

Abstract

Understanding the internal structure of specific landforms is a crucial prerequisite for determining their origin and evolution. Near-surface geophysics represents a non-invasive way of subsurface investigation, and it can be used to describe subsurface conditions, especially in protected areas. We tested possible hypotheses of block accumulations origin and evolution by four different geophysical methods (electrical resistivity tomography [ERT], shallow seismic refraction [SSR], ground penetrating radar [GPR], and electromagnetic induction [EMI]) in the Central European Uplands. At the same time, we evaluated the applicability of geophysical methods to determine the internal structure and thickness of block accumulations. Based on the application of two suitable methods (ERT and SSR), we (1) estimated the thicknesses of block accumulations, (2) partially described their internal structure, and (3) presented the most probable hypotheses of block accumulation origin and evolution in two investigated sites.

Could long glaciers have been extended in the Bohemian Forest? Geophysical insight from Groer Rachel region

“…Although the geophysical results are consistent with geomorphological mapping (Duffek et al, 2023b) and the geological map (LFU, 2021), they must be treated with caution due to the nature of geophysics (Otto and Sass, 2006;Schrott and Sass, 2008). The results could be combined with other geophysical methods (Sass, 2006;Tábořík et al, 2017;Břežný et al, 2021;Duffek et al, 2023a) such as shallow seismic refraction as recommended by e.g. Schrott and Sass (2008) or Duffek et al (2023a).…”

“…3 ERT results in the context of the detailed DEM, moraine complex boundaries (blue line) and more extensive glaciation boundaries (black dashed line) reported in Hauner (1980) and Hauner et al (2019). accumulations in the Bohemian Forest region were presented, for example by Duffek et al (2023a) who, based on geophysical analysis, lean towards a periglacial origin of these accumulations. The hypothesis of the occurrence of periglacially originated block accumulations is supported by the fact that the high resistivity bodies on P1 are located at the same level as the bedrock in the moraine complex (black dotted line on P1 Fig.…”

“…The results could be combined with other geophysical methods (Sass, 2006;Tábořík et al, 2017;Břežný et al, 2021;Duffek et al, 2023a) such as shallow seismic refraction as recommended by e.g. Schrott and Sass (2008) or Duffek et al (2023a). On the other hand, geophysical profiling in protected areas is probably the only option for the nondestructive investigation of subsurface conditions.…”

“…ERT is widely used in geomorphology (Šilhán and Pánek, 2007;Reynolds, 2011;Tábořík, 2012;Viles, 2016;Špaček et al, 2017;Břežný et al, 2018). Its suitability has been proven in investigations of the thickness of weathered mantle or sediments (Pellicer and Gibson, 2011;Tábořík, 2012;Duffek et al, 2023a) as well as glacial and periglacial landforms and permafrost (Kneisel, 2006;Hilbich et al, 2008;Krautblatter, 2010;Mentlík et al, 2010;Tábořík, 2012;Onaca et al, 2013;Engel et al, 2017;Duffek et al, 2023b). According to Tábořík (2012), the method can be used in glacially remodelled relief to determine the extent and thickness of glacial sediments and cirque and valley fills.…”

Deep learning–based inverse analysis of GPR data for landslide hazards

“…Compared to traditional methods of geophysical exploration, GPR has advantages such as a high detection efficiency, nondestructive probing, high precision, and robust interference resistance. It has been demonstrated to have an immense potential in applications such as landslide geological mapping, fault detection, and lithological identification (Hu and Shan, 2016;Hallal et al, 2019;Duffek et al, 2023). This noninvasive method can be used to rapidly and economically assess the internal conditions of landslides.…”