SeaTEM – A New Airborne Electromagnetic System for Bathymetric Mapping and Seafloor Characterisation

The potential for using airborne electromagnetic (AEM) methods for measuring water depth has been demonstrated from data acquired from several surveys over shallow coastal waters in Australia. These AEM surveys were undertaken using both fixed-wing time-domain and helicopter (time and frequency domain) commercial systems. Some survey data was also interpreted to delineate the bedrocksediment boundary which was in general agreement with marine seismic studies. These commercial AEM systems are designed for mineral exploration and are not optimized for marine surveying. Furthermore, these commercial AEM systems do not track the position of the towed sensor (bird). This research has now been extended by developing a helicopter time-domain AEM system (SeaTEM) which will include real-time kinematic tracking of the towed bird. Here we present data taken from the very first airborne trial over shallow water in Broken Bay (Australia). Preliminary interpretation of this dataset identifies the known bathymetry and depth to bedrock.