Comparative analyses on geophysical survey responses for various numerical models constructed based on field data

For the detection of contaminated zones based on geophysical surveys, we make numerical experiments since it is not easy to make or maintain contaminated test-beds for field surveys. In the numerical experiments, we numerically simulate and analyze the responses of geophysical surveys including electrical resistivity tomography (ERT), induced polarization (IP) and ground penetrating radar (GPR), for numerical models, each of which was constructed based on the results of field geophysical survey obtained from contaminated site. ERT, which can image electrical resistivity of subsurface, is one of the most common geophysical tools, while IP survey can provide additional electrical information of the subsurface. Besides GPR can suggest the structure of geology.

For each model, whose geological structure was composed as similar to that of the corresponding field-survey site, we first numerically simulated corresponding field surveys performed in the site and compare with field data to verify the properness of the model. For the verified models we performed numerical simulation of geophysical surveys about various scenario of contaminations (e.g., oil pollution, leachate, heavy metal, etc.), and analyzed resulting responses in order to make strategies for the detection of contaminated zones bases on geophysical surveys. Further, we considered time-lapse geophysical surveys for changing contamination scenarios with respect to time. In the case of models including clay media, the responses of IP were remarkable useful in locating the clay media when compared ERT-only survey.

This work was supported by the Energy Efficiency & Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20194010201920) and Korea Ministry of Environment as "The SEM projects; 2018002440005"