Resistivity Method
Electrical resistivity imaging is becoming increasingly popular due to
the availability of automated data acquisition devices and user-friendly
inversion software, which allows it to produce images of the subsurface
quickly and efficiently. It has
been used to look at areas with complicated geology, such as volcanic
and geothermal zones, landslides, seismotectonic structures,
hydro-geologic phenomena and environmental issues, and the deposition
and flow of impact melt and breccias (Colangelo et al., 2008;
Lapenna et al., 2005; Steeples, 2001 ). In this section, we focus on the
application of the resistivity method in investigating the Bosumtwi
impact crater.
Aning et al. (2013 ) used the multi-electrode gradient array to
conduct a 2D electrical resistivity tomography (ERT) survey at several
places around the crater. The authors discovered three formations with
distinct resistivity signatures: low resistivity regions from the lake’s
shore to uphill with resistivities of 64 Ω.m representing lake
sediments; moderately high resistivity regions with values between 128
Ω.m and 200 Ω.m interpreted as impact-related breccias such as dikes,
allochthonous or parautochthonous depending on their geometries; and
finally, the model clearly distinguished the resistive basement
metamorphic formations. Using the ERT model, the authors were also able
to determine faults and fractures and the thickness of post-impact lake
sediments and breccias. Based on their findings, they concluded that the
multi-core cable’s take-outs could be changed to suit the needs of a
specific survey, underlining the technique’s applicability in impact
cratering investigations and geo-electrical imaging studies in general.
Habimana et al. (2020 ) used electrical resistivity imaging
in conjunction with seismic refraction methods to map the subsurface
structure of the suevites north of the Bosumtwi impact crater in Ghana
to establish their depth extent, in-situ resistivity, and P-wave
velocity. According to the authors, the suevite deposits were discovered
at a depth of 12 meters. The findings also revealed that the subsurface
consists of two or three layers: unconsolidated topsoil, clayey soil,
and fractured claystone.