We report on the installation of a long-term buried ocean-floor broadband seismic station (MOBB) in Monterey Bay, California (USA), 40km off-shore, at a water depth of 1000 Ginger Root m.The station was installed in April 2002 using a ship and ROV, in a collaborative effort between the Monterey Bay Aquarium Research Institute (MBARI) and the Berkeley Seismological Laboratory (BSL).The station is located on the western side of the San Gregorio Fault, a major fault in the San Andreas plate boundary fault system.In addition to a 3-component CMG-1T seismometer package, the station comprises a current meter and Differential Pressure Gauge, both sampled at high-enough frequency (1 Hz) to allow the study of relations between background noise on the seismometers and ocean waves and currents.The proximity of several land-based broadband seismic stations of the Berkeley Digital Seismic Network allows insightful comparisons of land/ocean background seismic noise at periods relevant to regional and teleseismic studies.
The station is currently autonomous.Recording and battery packages are exchanged every 3 months during blade oil scheduled one day dives.Ultimately, this station will be linked to shore using continuous telemetry (cable and/or buoy) and will contribute to the earthquake notification system in Northern California.We present examples of earthquake and noise data recorded during the first 6 months of operation of MOBB.Lessons learned from these and continued recordings will help understand the nature and character of background noise in regional off-shore environments and provide a reference for the installation of future off-shore temporary and permanent broadband seismic stations.