Delineation of graves using electrical resistivity tomography

A suspected, old royal cemetery has been surveyed at the Kwame Nkrumah University of Science and Technology (MUST) campus, Kumasi, Ghana using Electrical Resistivity Tomography (ERT) with the objective of detecting graves in order to make informed decisions with regard to the future use of the area. The survey was conducted on a 10,000 m(2) area. Continuous Vertical Electrical Sounding (CVES) was combined with the roll along technique for 51 profiles with 1 m probe separation separated by 2 m. Inverted data results indicated wide resistivity variations ranging between 934 (tin and 600 Omega m in the near surface. Such heterogeneity suggests a disturbance of the soil at this level. Both high (>= 600 Omega m) and low resistivity (<= 74.7 Omega m) anomalies, relative to background levels, were identified within the first 4 m of the subsurface. These were suspected to be burial tombs because of their rectangular geometries and resistivity contrasts. The results were validated with forward numerical modeling results. The study area is therefore an old cemetery and should be preserved as a cultural heritage site. (C) 2016 Elsevier B.V. All rights reserved.