Insight Into Seismic Refraction and Electrical Resistivity Tomography Techniques in Subsurface Investigations

Abstract

Geophysical subsurface investigations use the principles of physics to unravel intrinsic Earth's subsurface features and nature of the underlying geology. Over the past two decades, the use of Seismic Refraction Tomography (SRT) and Electrical Resistivity Tomography (ERT) for subsurface investigations has greatly improved the quality of acquired data for two-and three-dimensional (2D and 3D) surveys. SRT employs more shotpoints and receivers than the conventional seismic refraction for its imaging technique. ERT uses automated multi-electrode array systems to improve the confidence of large and dense data collection. SRT and ERT techniques use powerful inversion algorithms to achieve high resolution subsurface inversion models for resolving subsurface characteristics and geological conditions over a complex and larger area that may be diffi cult with the use of their conventional methods. The 2D and 3D inversion models (tomograms) generated from the fi eld data sets of these techniques effi ciently ameliorate inaccurate subsurface boundaries and structural delineation with higher depth resolution, especially the 3D inversion models for areas of complex geology. These state-of-the-art techniques have extensively been used for groundwater, environmental, engineering and mining investigations among others. This study provides insight from theories to data inversion techniques for the known tomography techniques (SRT and ERT) in use for subsurface investigations.

Subsurface geological, hydrogeophysical and engineering characterisation of Etioro-Akoko, southwestern Nigeria, using electrical resistivity tomography

“…This electrode spacing was employed for higher depth penetration in order for the bedrock structures and architecture to be mapped. The Wenner array protocol was selected for the tomographic survey, because of its low sensitivity to noise (Loke 2004;Akingboye and Ogunyele 2019). Measurement procedures were repeated for other traverses after the completion of one profile.…”

“…The technique also plays important roles in geology and other large-scale site characterisation (Nguyen et al 2005;Dahlin et al 2007;Bery and Saad 2012;Binley et al 2015;Bernardinetti et al 2018;Dahlin and Loke 2018;Gourdol et al 2018;Mita et al 2018). The geotomograms of ERT can sufficiently delineate subsurface boundary conditions and also resolve difficulties with the mapping of complex structure and structural artefacts (Lok et al 2013;Carey et al 2017;Akingboye and Ogunyele 2019).…”

Shallow geophysical and hydrological investigations to identify groundwater contamination in Wadi Bani Malik dam area Jeddah, Saudi Arabia

“…Electrical resistivity profiling (ERP) provides valuable information on resistivity of subsurface material which will be used to create 2D and 3D resistivity models. The variation in resistivity values provides probable direction of landfill leachate flow in subsurface [10][11][12][13][14].…”

Electrical Resistivity Tomography for Sustainable Groundwater Development in a Complex Geological Area

“…Globally, people express a desire for abundant and potable groundwater for consumption and other purposes. Thus, exploration for the abundance of this hidden resource in the subsurface necessitates advancement in electrical resistivity imaging via the development of fast automated multi-electrode array systems and new inversion algorithms [1][2][3][4][5]. These systems clearly reveal the characteristics and conditions of the subsurface geology for sustainable groundwater development, particularly in the areas of complex geology.…”

“…Consequently, ERT remains a versatile technique for evaluating these geological factors for groundwater development and sustainability. ERT is a non-invasive surveying technique that images the subsurface from electrical resistivity measurements made at the earth's surface along a series of constant traverse separation with increasing electrode spacing at successive station positions [1,5,11]. This study, therefore, aimed at determining viable subsurface hydrogeological zones for groundwater development in Etioro-Akoko, a complex geological area where a layer of aquitard developed on the thin overburden, through the delineation of subsurface layers, structures/weak zones, and aquifer geometry and productivity.…”