Abstract The Gorda Ridge is an active slow rate (5.6 centimeters per year) spreading ridge located between 160 and 330 kilometers off the coasts of Northern California and Oregon. A prominent axial rift valley runs along the crest of the Gorda Ridge between the northern termination of the ridge at the Mendocino Fracture Zone and the northern termination at the Blanco Fracture Zone. At the northern end of the Gorda Ridge, the rift is located in a water depth of 3500 meters or 1000 meters below the crest height of the ridge. A multibeam narrow beam bathymetric survey system, using 2 2/3° wide acoustic beams was used to carry out a detailed survey of the rift valley and the Blanco Fracture, Gorda Ridge intersection zone. The SEABEAM system mounted aboard the NOAA Ship SURVEYOR shows an interesting mode of development of the Gorda Rift at this site. The rift valley, has in general, the bathymetric characteristics of the mid-Atlantic Ridge, namely the presence of a 250 meter high ridge located within the rift valley. This rift valley ridge is interpreted to be the site of active submarine volcanism. The rift valley is flanked by steep rift valley walls, located along normal faults. The width of the rift valley varies from 7 kilometers wide at the Blanco Fracture Zone to a width of less than 2 kilometers, at a distance of 24 kilometers south of the Blanco Fracture Zone. A multibeam survey, using the Navy SASS System was conducted over the axial portions of the Galapagos Ridge between 85°10' and 86°l5'W. The SASS survey of the Galapagos Ridge crest at 85°50'W and 0°45' shows the presence of a 2 kilometer wide rift valley striking in an east-west direction and flanked by normal faults. The south wall was surveyed in detail, using the deep diving submersible ALVIN. The dives showed evidence of recent volcanic extrusion along the axis of the rift valley and the presence of a field polymetallic sulphide stacks along the base of the normal fault at the south wall of the rift valley. Comparisons between the Gorda Ridge and Galapagos Ridge multibeam data located over the axes of these ridges shows close tectonic similarities. The Galapagos Ridge is now known to be a site of active volcanism, active hydrothermal activity and the site of polymetallic sulphide precipitates. The northern end of the Gorda Rift could also mark the site of ocean floor volcanism and polymetallic sulphide deposition. Introduction Major advances in ship-based echo-sounding techniques have cast a new light on the origins of small scale features of the ocean floor. The major advances have been possible through the introduction of ocean floor multibeam sounding techniques.