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www.obsip.org. 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. - PowerPoint PPT Presentation
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OBSIP OverviewInstrumentation Centers:Lamont-Doherty Earth Observatory
A. Barclay, J. Gaherty, M. Tolstoy
Scripps Institution of OceanographyJ. Babcock, A. Harding, G. Kent, J. Orcutt
Woods Hole Oceanographic Institution
J. Collins, K. Peal, B. Wooding
Oversight Committee:Doug Toomey, Chair, OregonRob Dunn, HawaiiJim Fowler, IRISGail Christeson, TexasFrancis Wu, Binghamton
Funded by the NSF, Marine Geology and Geophysics Program
J. Collins, J. Gaherty, D. ToomeyEarthScope National Meeting, May 12, 2009
www.obsip.org
• 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
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
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 Period Broad Band
LDEO - 30
SIO 67 41
WHOI 29 32
Total 96 103
Short Period instruments
• Vertical-component 2-4 Hz seismometer
• Hydrophone
• 24 bit A/D seismograph
• 60+ day recording at 200 Hz or betterMore info at
http://www.obsip.org
www.obsip.org
SIO BB
WHOI BB
LDEO BB
www.obsip.org
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
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
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
www.obsip.org
www.obsip.org
New WHOI Seismometer Burial System
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
Availability as of Jan 2009Broad-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
http://www.obsip.org
www.obsip.org
