Abstract : The results of an analysis of a complex data set acquired during the United States Geological Survey's Marine Crustal Deformation Study are presented. The experiment, which commenced in the spring of 1992 in a region of the Pacific known as the Juan de Fuca ridge, represents a first attempt to locally monitor plate dynamics in the marine environment using a network of tripod-mounted, dual-frequency acoustic transponders. The aim is to collect over a period of years time-series measurements of extension rates along the southern Juan de Fuca ridge. In addition, by collecting a combination of Global Positioning System satellite tracking data, low-frequency acoustics data, and water column pressure, conductivity, and temperature at depth, it was possible to extend geodetic control from land onto the seafloor. The methods to accomplish this latter goal of the experiment are described, as well as the final results. Baseline comparisons between several of the solutions obtained during this analysis are presented along with recommendations for additional data collection and analysis