Affiliation: | 1. Contractor to the U.S. Geological Survey, currently at University of Calgary, Department of Geoscience, ES118 2500 University Dr. NW, Calgary, AB T2N 1N4 Canada;2. Branch of Geophysics, U.S. Geological Survey, Office of Groundwater, Storrs, CT 06269;3. National Research Program, U.S. Geological Survey, Denver Federal Center, Denver, CO 80225;4. Environmental Sciences Division, Characterization and Monitoring Branch, U.S. Environmental Protection Agency, Las Vegas, NV 89119 |