Analysis of Full-Coverage Magnetometer Data in Relation to Statistically-Based Site Characterization Tools: Pueblo Precision Bombing and Pattern Gunnery Range No. 2 ESTCP Wide Area Assessment Demonstration

摘要

The recently completed Wide Area Assessment (WAA) at the Pueblo Precision Bombing and Pattern Gunnery Range (PPBR) provides a unique opportunity to compare geophysical data sets collected from both aerial and ground-based platforms, as well as use areas of 100 percent survey coverage to verify statistical approaches to UXO site characterization. Four distinct data sets have been collected at the PPBR: (1) A sparse ground-based magnetometer dataset collected along geophysical transects that cover 0.64 percent of the site area; (2) A dense ground-based transect dataset that covers 1.64 percent of the total site area and includes the sparse transect data set; (3) Ten small regions of the site within which 100 percent survey coverage was achieved using the groundbased magnetometer sensors; and (4) 100 percent coverage of the entire site with helicopter mounted magnetometers. The main issues addressed in this report are: (1) The consistency of the ground-based and helicopter-based magnetometer surveys in the areas where 100 percent coverage is available for both sensor modes; (2) The ability of the geostatistical kriging estimator to estimate spatially varying anomaly density from limited transect sampling as defined by comparison with the 100 percent helicopter-based surveys; (3) The ability of the kriging estimator to accurately estimate spatially varying densities and delineate high anomaly density areas within the 10 regions of 100 percent ground-based survey coverage from only limited transect data; and (4) The sensitivity of transect-based identification and delineation of high anomaly density areas to variations in the origin and orientation of the transects. Direct comparison of the number of geophysical anomalies identified by ground-based and helicopter-based sensor platforms in areas of joint 100 percent coverage show that the helicopter mounted sensors identify only 8 to 29 percent of the anomalies identified by the ground-based sensors.