1. OBSIP Overview Instrumentation Centers: Lamont-Doherty Earth Observatory A. Barclay, J. Gaherty, M. Tolstoy Scripps Institution of Oceanography J. Babcock, A. Harding, G. Kent, J. Orcutt Woods Hole Oceanographic Institution J. Collins, K. Peal, B. Wooding Oversight Committee: Doug Toomey, Chair, Oregon Rob Dunn, Hawaii Jim Fowler, IRIS Gail Christeson, Texas Francis Wu, Binghamton Funded by the NSF, Marine Geology and Geophysics Program J. Collins, J. Gaherty, D. Toomey EarthScope National Meeting, May 12, 2009 www.obsip.org

2. 1999: NSF-OCE funds new OBS designs and establishes U.S. National Ocean Bottom Seismic Instrumentation Pool (OBSIP). OBSIP is charged by NSF with providing state-of-the-art ocean-bottom seismic instrumentation and at-sea technical assistance for the collection of marine seismic data by the entire U.S. scientific community. Members are WHOI, SIO, and LDEO. To date (April 2009), 37 separate field program supported, involving 71 research cruises. Subscribed through 2011. OBSIP is funded via Cooperative Agreements with WHOI, SIO, and LDEO. Members receive modest annual, non-project specific, base suppot to maintain/upgrade their OBS fleet; all other support is tied to funded field programs. Ocean Bottom Seismology in the U.S. www.obsip.org

3. As of April 2009, OBSIP (WHOI,SIO, LDEO) has supported 37 separate field program, involving 71 research cruises. Red stars show locations of passive deployments; orange circles show locations of active-source experiments. OBSIP Experiments 2001-2009 www.obsip.org

4. Instrumentation Broad Band instruments 3-component seismometer spanning 0.01-10 Hz or better wide-band differential pressure gauge (DPG) and/or hydrophone High-resolution (24 bit) A/D seismograph 1+ year recording at 20-40 Hz Short PeriodBroad Band LDEO-30 SIO6741 WHOI2932 Total96103 Short Period instruments Vertical-component 2-4 Hz seismometer Hydrophone 24 bit A/D seismograph 60+ day recording at 200 Hz or better More info at http://www.obsip.org www.obsip.org

5. SIO BB WHOI BB LDEO BB www.obsip.org

6. Challenges and Limitations Free-fall design – No control on seismometer placement (poor coupling) – Susceptible to bottom currents (tilt noise) and trawling Poor performance of horizontal components Long-duration deployments limited to depths greater than 1000 m, even greater in heavy fishing regions – High risk with many potential failure points Glass flotation – maximum depth ~6000 m No GPS timing – clock drift rates of 2-5 ms/day No SOH, no intermediate data recovery www.obsip.org

7. New Developments Trawl-resistant mounts – Allow for shallow (shelf) deployments Sub-seafloor burial system – Improve noise characteristics in both shallow and deep water Ultra broad-band bottom-pressure sensors – Detect vertical deformation with 1 mm precision from DC to 10 Hz Three-component accelerometers – On-scale near-fault deployment ROV recovery – Reduce risk of loss and enhance data recovery Near-shore buoy telemetry – GPS timing and real-time data recovery www.obsip.org

8. Borehole Buried Seafloor Seafloor SP Borehole Buried Seafloor Seafloor SP Horizontal components on buried seismometer (red traces) are much less noisy at long periods than the horizontal components of an identical seismometer sitting on the seafloor (blue traces). Performance Gain Achieved by Seismometer Burial Collins et al., GRL, 2001 www.obsip.org

10. New WHOI Seismometer Burial System

11. Scheduling Fill out instrument-request form (obsip.org) prior to proposal submittal – OBSIP provides cost-estimate to be included as supplemental information in proposal (not in budget) Scheduled in order of official funding – In conjunction with ship scheduling Non-NSF projects allowed, but have lower priority in scheduling More info at http://www.obsip.org www.obsip.org

12. Availability as of Jan 2009 Broad-Band Fully booked through 2010 (pending ship schedules) – Wiens, Forsyth, Baldwin, Kohler ~ 44-52 instruments now scheduled through much of 2011 – Baldwin, Kohler, Wiens Short-Period Dependent on cruise schedule of (usually) the Langseth In general available for short duration (< 60 day) experiments. More info at http://www.obsip.org www.obsip.org

13. http://www.obsip.org www.obsip.org