Carol A. Finn P. Hill R. Kucks J. Phillips R. Blakely C. Bouligand T. Sabaka A. Elshayat A. Aref E. Elawadi D. Ravat 2009 Under an initiative started by Thomas G. Hildenbrand of the U.S. Geological Survey, we have improved the long-wavelength (50-2,500 km) content of the regional magnetic anomaly compilation for the conterminous United States by utilizing a nearly homogeneous set of National Uranium Resource Evaluation (NURE) magnetic surveys flown from 1975 to 1981. The surveys were flown in quadrangles of 2 deg of longitude by 1 deg of latitude with east-west flight lines spaced 4.8 to 9.6 km apart, north-south tie lines variably spaced, and a nominal terrain clearance of 122 m. Many of the surveys used base-station magnetometers to remove external field variations. application/pdf 10.3133/ofr20091258 en U.S. Geological Survey A preliminary, full spectrum, magnetic anomaly grid of the United States with improved long wavelengths for studying continental dynamics: A website for distribution of data reports