The Provision of Ocean-Bottom Seismographs

The Ocean-Bottom Instrumentation Facility (OBIF) has a successful track record of over 15 years of deploying a range of autonomous sensors on the seabed. OBIF is funded by the UK's Natural Environment Research Council (NERC) and operated jointly by the Universities of Southampton and Durham to support researchers in a range of environmental science disciplines. We carry out deployments in water depths ranging between 10's of m and 5500 m for periods from a few days to a year to measure parameters such as ground vibration, pressure, and electric and magnetic field strengths. OBIF currently have a fleet of 55 autonomous seabed instruments, with a physical platform (flotation, pressure tubes, acoustic releases) modified from an original Scripps Institution of Oceanography design, although the current generation of loggers are an internal OBIF design. For measuring vibrations, we currently use high-frequency sensors. We have been awarded NERC capital funding to extend our capability by purchase of a number of market-established broadband ocean-bottom seismographs. We wish to procure a small number (5-10 depending on cost) of broadband ocean-bottom seismographs to assess their interoperability with our existing instrument pool, with a view to expansion of these numbers in the mid-to-longer term. They will be used primarily for solid Earth imaging using natural sources of seismic energy(e.g. earthquakes, ocean waves) but will also be used in experiments that use manmade controlled seismic sources (e.g. airguns).