1. Boone Pickens School of Geology; Oklahoma State University; Stillwater; Oklahoma; USA
2. U.S. Environmental Protection Agency; Las Vegas; Nevada; USA
3. Department of Earth and Environmental Sciences; Rutgers University; Newark; New Jersey; USA
4. Department of Geophysics; Colorado School of Mines; Golden; Colorado; USA
5. U.S. Geological Survey; Denver; Colorado; USA