Of apparent interest to the defense nuclear agency (DNA) is the ability to detect the location of tunnel boring machines (TBM).These Types of devices are used to drill tunnels for military purposes, such As the storage of nuclear devices and the construction of missile Silos. By locating TBM's in operation, unfriendly forces could Identify potential military targets. It is therefore of interest to DNA to determine to what extent TBM's can be located, and thus develop anti-detection methods. Also, of interest to other military Agencies is the detection of clandestine tunneling by hostile forces. The TBM is known to generate a continuous seismic signal while operating. Utah geophysical, inc. (UGI) has developed a seismic drill bit Positioning method (U.S. patent #4,460,059) that should be applicable To locating a TBM. This technique uses a beam-steering array processing procedure to detect coherent continuous seismic events in Poor signal to noise environments. UGI proposes to investigate the Feasibility of using particle motion prefiltering to enhance the Coherency values of the processed data, thereby improving on the Likelihood of locating a TBM with the existing technology.
