Airborne electromagnetic and magnetic survey results from the Upper San Pedro Basin, Arizona, 1997 and 1999

Airborne electromagnetic (EM) and magnetic survey data were collected by GeoTerrex Ltd. in the Upper San Pedro Basin and Fort Huachuca, Arizona in 1997 and 1999. EM data were collected using a time-domain GEOTEM system towed behind a fixed-wing aircraft with 30Hz cycle rate, 696,000 Am2 dipole moment, and 4 ms pulse width. Magnetic data were collected using a CS-2 cesium vapor magnetometer. Approximately 2,250 line-km were flown. Nominal line spacing was 400–800 m and nominal system height above land surface was 125 m for the electromagnetic sensor and 75 m for the magnetic sensor. Numerical inversions to recover layered resistivity structure were prepared by Condor Consulting, Inc. using the AIRSTEM proprietary inversion code. Average depth of investigation was 400 m. Raw data and AIRSTEM inversions done by Condor Consulting, Inc. are provided in a Geosoft database (Seequent, Inc.). Inverted data are also provided in an XYZ Ascii format. Multiplots showing the AIRSTEM inversion along each transect are provided as PDFs. Original contractor data packages contain raw electromagnetic and magnetic data, positional information, and system information in the original delivered formats (UpperSanPedroAEM_Huachuca_ContractorDataPackage_GeoTerrexLtd_1997.zip and UpperSanPedroAEM_SierraVista_ContractorDataPackage_GeoTerrexLtd_1999.zip). These packages are described in contractor-provided readme.txt files.

These data support the interpretive findings in:
Wynn, Jeff, 2006, Mapping ground water in three dimensions—An analysis of airborne geophysical surveys of the upper San Pedro River basin, Cochise County, southeastern Arizona: U.S. Geological Survey Professional Paper 1674, https://doi.org/10.3133/pp1674