Improved Near Surface Mapping in Groundwater Studies: Application of Fast-sampling TDEM Methods
Australian Society of Exploration Geophysics (ASEG), Groundwater Preview Feb., 2002.
Michael Hatch, Zonge Engineering and Research Organization (Australia) Pty Ltd.;
Brian Barrett, Department of Geology and Geophysics, Adelaide University, Adelaide, SA;
Darren Bennetts, Department of Earth Sciences, La Trobe University, Bundoora, VIC;
Graham Heinson Department of Geology and Geophysics, Adelaide University, Adelaide, SA;
Andrew Telfer, Australian Water Environments Pty Ltd, Adelaide, SA;
Craig Roberts, Peak Gold Mines, Cobar, NSW.
Paper — [pdf] GRW_TDEM_NearSurfaceMapping
Often the goal of these surveys is to help geologists and engineers determine whether their assumptions on well location and water flow are correct. Techniques that have been used include shallow seismics (Bachrach and Nur, 1998), DC resistivity (Benson et al., 1997), ground penetrating radar (Hagrey and Muller, 2000), frequency domain electromagnetics (FDEM) (Acworth, 2001), and time domain electromagnetics (TEM) (Yang et al., 1999).
Recent advances in sampling speed, circuitry speed, and data recording have allowed the development of TEM techniques where data can be taken faster (and therefore start closer to the surface), and with better resolution of the top 15-50 meters. These techniques include the Zonge Engineering NanoTEM system and the fast-sampling modifications to the SIROTEM-3 system.