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… More

Fireflood or steamflood enhanced oil recovery (eor) processes are commonly used in the recovery of heavy oils ortar sands. to optimize the use of these processes, the operator needs to know the velocity, location and direction of movement of the thermal flood front. to obtain this imformation using… More

Vertical seismic profiles (vsps) provide information for more precisely interpreting into geophysical seismic data, as well as geophysical information beyond the limits of the wellbore. the high degree of redundancy necessary to acquire this type of data, and the complications that can arise from… More

External moonitoring devices for detecting humans hiding in vehicles are needed to prevent unauthorized access to restricted military areas and to prohibit illegal immigrants from entering the united states at border crossings. several investigators have found that a seismometer, placed on a… More

Small seismic events occur continuously at random time intervals within the earth. These events have been referred to as ambient noice, microtremors, or microseisms. Randomly occurring micro- seisms can be compressed into a single source-pulse and the earth's reflectivity function by taking the… More