GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 3.2 GNGTS 2024 Applicaton of conductve textle sachets as electrodes for electrical resistvity tomography measurements collected on debris and coarse- blocky surfaces M. Pavoni 1 , J. Boaga 1 , A. Bast 2,3 , Lichtenegger 2,3 , J. Buckel 4 1 Department of Geosciences, University of Padova, Padova, Italy. 2 WSL Insttute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland. 3 Climate Change, Extremes and Natural Hazards in Alpine Regions Research Center CERC, Davos Dorf, Switzerland. 4 Insttute for Geophysics and Extraterrestrial Physics, Technische Universität Braunschweig, Braunschweig, Germany. 1. Abstract Electrical resistvity tomography surveys are commonly applied in geophysical investgatons performed in high mountain environments where debris and coarse-blocky surfaces can be found, e.g. landslide or rockfall deposits, blocky slopes and rock glaciers. In this harsh situaton, obtaining acceptable contact resistances between the electrodes, usually composed of stainless-steel spikes, and the ground surface is challenging. The electrodes must be steadily coupled between the boulders (e.g. by hammering them) and, to improve the galvanic contact, sponges soaked in salt water are typically inserted among the spike and the rock surface (Hauck and Kneisel, 2008). Considering all this, it is clear that deploying ERT arrays in these environments is partcularly tme- consuming. To decrease this tme efort, recently Buckel et al. (2023) applied conductve textle sachets as electrodes in ERT surveys performed on rock glaciers. To verify the reliability of this new electrodes approach, in this work we intensively tested the conductve textle sachets electrodes in diferent envinroments with debris and corse-blocky surfaces. 2. Introducton It is well known in the geophysical community that collectng a high-quality ERT dataset requires a good galvanic contact between the electrodes and the ground surface (Day-Lewis, 2008). The parameter that represents the electrical contact area of two materials is defned as contact resistance. Low values of contact resistance allow to easily inject the electrical current and consequently to acquire ERT datasets with higher signal to noise rato (Pavoni et al., 2022). This conditon is partcularly challenging to be achieved in envinroments with debris and corse-blocky surfaces. Coupling the electrodes with sponges soaked in salt-water is an efcient soluton to minimize the contact resistance (Hauck and Kneisel, 2008). Despite this, the approach requires a signifcant amount of tme to deploy the entre electrodes array, and a considerable amount of salt water to wet the sponges. Considering this, Buckel et al. (2023) proposed an alternatve electrodes system to facilitate the preparaton of ERT arrays in rock glacier envinroments. Instead of the traditonal steel spikes, conductve textle sachets (wet with salt-water) are used as electrodes. In