An experimental seismoelectric survey for groundwater exploration in the Australian outback

Theoretical and experimental studies suggest that electric fields induced by seismic waves via electrokinetic coupling may be used to image subsurface boundaries where there is a contrast in pore fluid chemistry, permeability, or elastic properties. Such seismoelectric conversions are, however, challenging to measure in the field. In July, 2001, we conducted a field trial of combined seismoelectric and seismic reflection profiling in an effort to detect a sand aquifer at 40 m depth within a buried paleochannel system near Leonora, Western Australia. Our instrumentation included new lower-noise preamplifiers and an expanded recording system designed to detect weaker signals than those we had measured elsewhere at much shallower depths (e.g. Butler et al., 1996). In this paper, we present the survey design and the approaches used to combat noise, and compare the coherent events present on seismic and seismoelectric shot records. The seismoelectric records are dominated by events that appear to be associated with seismic waves sweeping by the dipole antennas. While these arrivals may contain useful information in their own right, they also have the unfortunate effect of hiding any seismoelectric conversions that may be generated at subsurface interfaces such as the top of the sand aquifer. Applications of seismic processing routines, such as radial trace transform filters, that discriminate against events with significant linear moveout are considered as an approach to attenuate the undesired coherent noise trains.