| For over 40 years, the US government has been involved in nuclear weapons production. Byproducts of this work were commonly deposited in shallow pits and trenches. It is now required by state and federal regulatory agencies to perform thorough site characterization and remediation. An introduction to subsurface geophysical methods is presented as applied to environmental site characterization. A review of geophysical environmental methods for site characterization and geomagnetic literature is presented. Forward, or direct, models are developed for geomagnetic problems, followed by a description of a general, robust single and multiple sensor optimization method. These methods are applied to the analysis of two sites at Sandia National Laboratories, Technical Area II and a cold test pit in Technical Area III, using total field magnetometer and EM61 survey data. The advantage of using a multi-sensor inversion method to obtain unique solutions from magnetic and EMI data is demonstrated using both simulated and measured data. |
