Characterization of Sobradinho landslide in fluvial valley using MASW and ERT methods

Abstract

Landslides can substantially impact the fluvial systems, which is why the continuous mapping of their extent, evolution and stability assessment is crucial. However, in such environments, material identification (e.g. colluvium) and subsurface characterization by the methods used for geologic mapping and geotechnical investigation is often a challenging task. Thus, these classical invasive methods may benefit from geophysical techniques to enable and enhance our understanding of the subsurface in these areas. To examine such integrated approach, Multi-Channel Analysis of Surface Waves (MASW) combined with Electrical Resistivity Tomography (ERT) were applied on a geomorphologically active fluvial valley in Sobradinho (the Federal District of Brazil). The subsurface materials showed a specific range of resistivity values as dry soil, saprolite, and landslide slip surface. The 1D shear wave velocity (Vs) model showed an increasing trend of Vs with depth at a location away from the landslide mass, while the longitudinal profile (over the landslide) showed an anomalous change in Vs (~ 250 to 400 m/sec). Based on the existing information about the landslide, the ERT appeared to be an effective method over MASW. This study shows how the integration of geophysical data with the geological and geotechnical investigation helps to obtain a more realistic or unambiguous model of the subsurface.

Seismic Signatures and Site Characterization of an Intermittent Stream in Dry and Flood Conditions: An Implication for Soil Losses and Landslide Triggering

“…Therefore, we consider this position reflected by the black low coherence value in the valid region as the susceptible points to erosion. For instance, soil voids or discontinuity can provide permeable paths where rain water can infiltrate into the subsurface and may cause instability by building pore water pressure [82] . The average energy attribute can be used to delineate the presence and geometry of buried pebbles or boulders to the fact that the interface of rock and soil can reflect high energy waves with significant differences in electrical properties among them.…”

“…Therefore, we consider this position reflected by the black low coherence value in the valid region as the susceptible points to erosion. For instance, soil voids or discontinuity can provide permeable paths where rain water can infiltrate into the subsurface and may cause instability by building pore water pressure[82] .…”

The Potential Use of Geophysical Methods to Identify Cavities, Sinkholes and Pathways for Water Infiltration

“…Different earth materials have different resistance to the passage of current because of the variation in the degree of fractures, material types and degree of saturation. Both the injection of current and the detection of potential difference are carried out using four metal electrodes, current and potential, respectively [42]. The way in which these electrodes are configured has a direct influence on the results, and there are two adopted ways in which electrodes are configured as (i) vertical electrical sounding (VES) and (ii) profiling.…”

Characterization of an active landslide structure with integrated electrical resistivity tomography and multi‐channel analysis of surface waves methods in Değirmendere district, Sakarya (Türkiye)

“…Geophysical methods in landslide studies have become prominent in the last two decades due to their more flexible, fast, costless, non‐destructive, high‐resolution determination of the internal structure, slip plane, hydro‐geological, movement character and mechanical properties of the landslide (Hibert et al, 2012; Imani et al, 2021; Zhou et al, 2022). In this context, electrical and seismic methods from geophysical methods are the most preferred in landslide areas (Göktürkler et al, 2008; Hussain et al, 2020; Perrone et al, 2021; Yalcinkaya et al, 2016; Yilmaz, 2007). These methods focus on the physical properties of the sliding material in the lateral–vertical direction.…”