Abstract: An autonomous sensor node for undersea seismic surveying is formed as a sphere with density similar to sea water in order to minimize effects of noise. The node is capable of measuring both seismic pressure waves and water-borne particle velocity in three dimensions. The node floats above the seafloor to greatly decrease the impact of shear wave noise contamination generated by seabed waves. The node is attached to an anchor resting on the seabed by a tether. The tether is configured to prevent transfer of any tensile forces caused by shear waves in the seabed stratum from the anchor to the node. The tether may have a varying density along its length to entirely attenuate any force transfer from the seafloor.

Abstract: A connection system for connecting external devices to a streamer. The connection system comprises three outer collars maintained collinearly aligned by a stabilizing member, such as a lightweight, rigid tube, attached to each outer collar. The tube extends parallel to the bores of the outer collars. The forward and aft outer collars ride on races formed on the periphery of inner collars clamped around mounting structure in the interior of the streamer. An external device is attached to the forward collar and to the intermediate collar, which does not ride on an inner collar. The spacing between the forward and intermediate collars is fixed by the standard spacing of the two attachment points in standard external devices. The spacing between the forward and aft collars is set by the specified spacing of mounting structures in the interior of the streamer.

Abstract: A connection system for connecting external devices to a streamer. The connection system comprises three outer collars maintained collinearly aligned by a stabilizing member, such as a lightweight, rigid tube, attached to each outer collar. The tube extends parallel to the bores of the outer collars. The forward and aft outer collars ride on races formed on the periphery of inner collars clamped around mounting structure in the interior of the streamer. An external device is attached to the forward collar and to the intermediate collar, which does not ride on an inner collar. The spacing between the forward and intermediate collars is fixed by the standard spacing of the two attachment points in standard external devices. The spacing between the forward and aft collars is set by the specified spacing of mounting structures in the interior of the streamer.