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Clearing Unexploded Ordnance: Bayesian Methodology for Assessing Success

Description: The Department of Defense has many Formerly Used Defense Sites (FUDS) that are slated for transfer for public use. Some sites have unexploded ordnance (UXO) that must be cleared prior to any land transfers. Sites are characterized using geophysical sensing devices and locations are identified where possible UXO may be located. In practice, based on the analysis of the geophysical surveys, a dig list of N suspect locations is created for a site that is possibly contaminated with UXO. The suspect locations on the dig list are often assigned into K bins ranging from ``most likely to contain UXO" to ``least likely to be UXO" based on signal discrimination techniques and expert judgment. Usually all dig list locations are sampled to determine if UXO is present before the site is determined to be free of UXO. While this method is 100% certain to insure no UXO remains in the locations identified by the signal discrimination and expert judgment, it is very costly. This paper proposes a statistical Bayesian methodology that may result in digging less than 100% of the suspect locations to reach a pre-defined tolerable risk, where risk is defined in terms of a low probability that any UXO remains in the unsampled dig list locations. Two important features of a Bayesian approach are that it can account for uncertainties in model parameters and that it can handle data that becomes available in stages. The results from each stage of data can be used to direct the subsequent digs.
Date: October 30, 2005
Creator: Anderson, K K.
Partner: UNT Libraries Government Documents Department

Special Issue on geophysics applied to detection and discrimination of unexploded ordnance

Description: Unexploded ordnance (UXO) presents serious problems in Europe, Asia, as well as in the United States. Explosives and mines from World War I and World War II still turn up at European and Asian construction sites, backyard gardens, beaches, wildlife preserves and former military training grounds. The high rate of failure among munitions from 60-90 years ago is cited as one of the main reasons for such a high level of contamination. Apart from war activities, military training has resulted in many uncovered ordnance. It is especially true in the United States, where most UXO has resulted from decades of military training, exercises, and testing of weapons systems. Such UXO contamination prevents civilian land use, threatens public safety, and causes significant environmental concern. In light of this problem, there has been considerable interest shown by federal, state, and local authorities in UXO remediation at former U.S. Department of Defense sites. The ultimate goal of UXO remediation is to permit safe public use of contaminated lands. A Defense Science Board Task Force Report from 1998 lists some 1,500 sites, comprising approximately 15 million acres, that potentially contain UXO. The UXO-related activity for these sites consists of identifying the subareas that actually contain UXO, and then locating and removing the UXO, or fencing the hazardous areas off from the public. The criteria for clearance depend on the intended land end-use and residual hazard risk that is deemed acceptable. Success in detecting UXO depends on the ordnance's size, metal content, and depth of burial, as well as on the ability of geophysical systems to detect ordnance in the presence of metallic fragments from exploded UXO and other metal clutter.
Date: January 15, 2007
Creator: Gasperikova, Erika; Gasperikova, Erika & Beard, Les P.
Partner: UNT Libraries Government Documents Department