Electrical resistivity tomography (ERT) was carried out around a municipal solid waste dumpsite with the objective of monitoring spatial and temporal variations of dumpsite emissions in soil and groundwater along four (4) traverse lines. Results show that the baseline exhibits less spatial and temporal variations in resistivities than the monitor data along each traverse. The study revealed that the dumpsite was in its exothermic phase of activity in the first two years of active waste dumping and endothermic at the cessation of waste dumping and final reclamation after four years of operation. The exothermic phase was characterized by the production of enormous volumes of leachate and relatively conductive waste gases, predominantly Carbon dioxide (CO2), Hydrogen sulphide (H2S) and Ammonium (NH3), by infiltrating rainwater through the waste pile, groundwater inflow and aerobic decomposition of waste matter. The endothermic phase is accompanied by the production of more waste gases than leachate, especially the non-conductive methane gas (CH4) and nonmethane volatile organic compounds (VOCs) by the anaerobic decomposition of waste matter due to compaction effects resulting in the inhibition of the circulation of oxygen-rich air within the waste pile. The dump was observed to be at the peak of its methanological phase during the endothermic cycle. This is especially pronounced in the resistivity of the monitor data situated at the edge of the dumpsite, which exhibits anomalously high resistivities compared to the baseline due to increased non-conductive methane gas generation, VOCs, and reduced temperature within the dump. The reference data exhibits intermediate resistivities relative to the traverses closer to the dumpsite. The waste gases dominate at this offset, while the impact of leachate has considerably reduced.