AN EMPIRICAL TIME-DEPTH MODEL FOR CALCULATING WATER DEPTH, NORTHWEST GULF-OF-MEXICO

The velocity of sound in water varies nonlinearly with depth in temper ate and tropical ocean basins, limiting the accuracy of representing w ater velocity with a single average value. A seventh-order polynomial provides an empirical model for converting seismic travel time to wate r depth in the northwest Gulf of Mexico. This method works best for th e continental slope where relief can vary markedly over salt structure s, whereas application on the shelf is limited by local and seasonal v ariations in water velocity. Calculated depths may differ from those o f other techniques because of difficulties interpreting competent wate r bottom.