Saturation in the vadose zone is known to reduce the ground penetrating radar (GPR) electromagnetic wave velocities. We examine the impact of increased water content in highly-permeable beach and dune systems on GPR velocities along coastal margin of Perth, Western Australia. We acquire repeat GPR transects in May and August before and after annual high rainfall periods. The assumption of exceedingly flat water table reflector permits us to estimated change in GPR velocity at successive dates. This change in velocity can be translated to an estimated change in water saturation via the Topp relationship which is an imperial mapping of water saturation to dielectric permittivity.

The generation of electric fields with electric bipole transmitters are applicable at a wide range physical scales and for many subsurface exploration endeavors. Increase in transmitter power for a wide range of waveforms combined with receiver sensitivity has led to deeper exploration with electromagnetic methods. We investigate the optimal design of grounded bipole EM system for generation of electromagnetic fields over a basin-scale fault in Perth, W.A. The technical objective is to recover detailed electrical conductivity distribution proximal to and within a large fault system to depths of as much as 1000m below the surface. The ultimate geological imperative for the exercise is reveal possible change in solute concentration or hydraulic across these large fault systems. For example, imaging of the difference composition of fault core zone would be a valuable outcome. We investigate various combinations of receiving and transmitting antenna geometries in preparation for a field campaign intended to resolve electrical parameters and structures of this large fault system.