9403409 Purdy The distribution and characteristics of microearthquake activity across the Endeavour segment of the Juan de Fuca ridge will be studied by deploying a network of 15 ocean bottom seismometers for a two month period. The array will span the axial valley in the vicinity of the main vent field and the western flanks out to about 15 km. The objectives of the experiment are to characterize the distribution and nature of offaxis microearthquake activity and to use these data to evaluate and refine existing models of the tectonic evolution of yound oceanic crust as it moves off axis, and to estimate the depth of the brittle-ductile transition from the maximum depth of seismicity as a function of distance from the ridge axis. ***
