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A comparison of helicopter-borne electromagnetic systems for hydrogeologic studies

January 1, 2016

The increased application of airborne electromagnetic surveys to hydrogeological studies is driving a demand for data that can consistently be inverted for accurate subsurface resistivity structure from the near surface to depths of several hundred metres. We present an evaluation of three commercial airborne electromagnetic systems over two test blocks in western Nebraska, USA. The selected test blocks are representative of shallow and deep alluvial aquifer systems with low groundwater salinity and an electrically conductive base of aquifer. The aquifer units show significant lithologic heterogeneity and include both modern and ancient river systems. We compared the various data sets to one another and inverted resistivity models to borehole lithology and to ground geophysical models. We find distinct differences among the airborne electromagnetic systems as regards the spatial resolution of models, the depth of investigation, and the ability to recover near-surface resistivity variations. We further identify systematic biases in some data sets, which we attribute to incomplete or inexact calibration or compensation procedures.

Publication Year 2016
Title A comparison of helicopter-borne electromagnetic systems for hydrogeologic studies
DOI 10.1111/1365-2478.12262
Authors Paul A. Bedrosian, Cyril Schamper, Esben Auken
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Prospecting
Index ID 70189094
Record Source USGS Publications Warehouse
USGS Organization Crustal Geophysics and Geochemistry Science Center