Saltmap - High Resolution Airborne Em For Electrical Conductivity Profiling

Shallow conductivity mapping using airborne electromagnetic systems has been used extensively in<br>Australia for environmental applications. The aim of such surveys is to define near surface<br>conductivity variations which can be related to dissolved salts in the groundwater. In most parts of<br>Australia the principal salt is naturally occurring sodium chloride (NaCl) and in many cases salt<br>deposits are concentrated or remobilised by the effects of man’s interaction with the environment.<br>To understand how these deposits are moving in the ground it is necessary to map the conductivity<br>variations in the near surface in three dimensions. The airborne electromagnetic system employed<br>must measure both at high frequency and at high sampling rates to achieve this aim. To resolve<br>conductivity structures at high resolution in the ground’s near surface is in some ways a more<br>difficult problem than to detect anomalies at great depth. A wider system bandwidth and superior<br>noise immunity are required and consequently greater real-time computing power. Results from the<br>initial surveys using SALTMAP show that most of the planned specifications of the system have<br>been met. The challenge for the future is to utilise the data generated in remedial environmental<br>work.