Rapid Screening Of Large-Area Magnetic Data For Unexploded Ordnance

Airborne magnetic surveys can cover hundreds of hectares with very close sensor spacing<br>in a single day. Over unexploded ordnance (UXO) contaminated areas this can translate to<br>thousands of anomalies. Any tool that permits one to rapidly classify anomalies as probable non-<br>UXO and probable UXO is useful. Several geophysical characteristics can be exploited to sort<br>the anomalies, among them signal amplitudes, estimated source depth, and indicators of<br>magnetic remanence. We have developed a grid-based technique that combines information<br>from the total field residual anomaly, the analytic signal, and sensor height to estimate source<br>depth and remanent magnetization. We can then use these and other indicators in statistical<br>schemes to predict whether the source of an anomaly is or is not ordnance.