Delineation of graves and other subsurface features using electrical resistivity tomography
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Date
September, 2015
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Abstract
In response to rumours that the study area (a relatively
at ground) used to be a royal
cemetery and for future developmental purposes, this study aimed at delineating graves
and other subsurface features so that informed decisions can be made about the place if
the need arises. The survey was conducted on a 10000 m2 plot of land using the electri-
cal resistivity method. The multi-electrode or CVES was combined with the roll along
technique for data collection. With inter pro le separation of 2 m, 51 pro le lines were
obtained. The data were acquired in 2D with a minimum electrode separation of 1 m and
later collated to 3D. The gradient array was used taking the Grad4L8 and Grad4S8 pro-
tocols into consideration. Data processing with the RES2DINV and RES3DINV software
indicated wide resistivity variations in the near subsurface suggesting a disturbance of the
soil at this level. This might have been caused by digging (probably graves) and re lling
activities . High and low resistivity anomalies relative to their backgrounds were identi-
ed within the rst 4 m of the subsurface. These were suspected to be tombs because
of their rectangular geometries, dimensions and resistivity contrast with the background
materials. The linear arrangement of these anomalies similar to the arrangement of tombs
in cemeteries heightened this suspicion. Other subsurface features observed were also as-
sociated with dykes, unweathered granite, cracks, voids etc. Consequently, the study area
could have been a cemetery but can still support infrastructural development since the
entire place was not covered by the anomalies. A weak zone spotted between 26 and 58
m in the S-N direction and between 30 and 70 m in the E-W direction must however be
taken into consideration when carrying out constructional projects in the study area.
Description
A thesis submitted to the Department of Physics, Kwame Nkrumah
University of Science and Technology in partial fulfillment of the
requirements for the degree of
Master of Philosophy(Geophysics), 2015