• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
The Ocean Bottom Seismometer

The Ocean Bottom Seismometer



A brief presentation on the ocean-bottom seismometer, including how it works

A brief presentation on the ocean-bottom seismometer, including how it works



Total Views
Views on SlideShare
Embed Views



0 Embeds 0

No embeds



Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
Post Comment
Edit your comment

    The Ocean Bottom Seismometer The Ocean Bottom Seismometer Presentation Transcript

    • Keygan Sands
    •  Measures tectonic movement* 90% earthquakes occurunderwater* Motions may be <1mm or >1m* Uses: Calculating quake energy* Predicting quakes* Studying structure of mantle andcrust**Ocean InstrumentsCollins 2004
    •  Rests on and moves withseafloor* Heavy mass swings betweentwo magnets* Oscillations produce electricalcurrent* Cylindrical body housesinstruments, batteries and datalogger housed separately* 60-600kg instrument package**Ocean InstrumentsOcean Instruments
    •  Developed in 1970s by institutions (WHOI, SIO,University of Texas)* Inefficient: high power, limited storage capacity,inexact clocks* Formation of National OBS Instrumentation Pool in1999 by NSF with first major long-term deployment in2004* Modern OBSs are lower power, higher precision clocks,sensitive to finer motions* Divided into short and long period OBSs**Collins 2004
    •  Short-period OBS (WHOI D2 and L-CHEAPO): High-frequency motions* Small quakes* Studies outer layers of crust* 60 day to 6 month deployment period** Long-period OBS (WHOI and Scripps long-deployment): Broader range of motions* 10/sec to 1/min data collection* Mid-sized quakes, distant activities* >12 month deployment period***Ocean Instruments**OBSIP, National Science FoundationOBSIP, NSF
    •  Good: Stable clocks Easily recovered data Connectable to surfaceobservatories Easily deployed (requireswinch) Bad: Imprecise installation Short-period have shortbattery lives High data Ocean InstrumentsOcean Instruments
    •  “Structure of the East Pacific Rise from an OceanBottom Seismometer Survey” –Orcutt andKennett, 1976 Physical structure of sea floor studied Determined that oceanic crust structure can changerapidly depending on age (velocity of earthquakewaves through medium) “Earthquake distribution in the subduction zoneoff eastern Hokkaido, Japan, deduced from ocean-bottom seismographic and land observations” –Iwasaki et. al, 1991 Observations of microearthquakes on continentalslope of Japan Determined that several tectonic blocks exist in thesubduction zone along Kuril Trench (differences inseismicities between locations)
    •  “A Sea-Floor Spreading EventCaptured by Seismometers” –Tolstoyet. al, 2006 Monitoring of East Pacific Rise duringridge eruption and precursor activity Developed a profile of major spreadingevent Eruptions can be used to forecastspreading “Tracking fin whales in the northeastPacific Ocean with a seafloor seismicnetwork” –Wilcock, 2012 Use of OBSs to passively monitor whalelocations Microearthquakes: 10Hz, whale calls:20HzLife of Sea
    • Collins, John (2004). “Listening Closely to „See‟ Into the Earth.” Oceanus.<http://www.whoi.edu/oceanus/viewArticle.do?id=2509&archives=true>Iwasaki, T., Hirata, N., Kanazawa, T. Urabe, T., Motoya, Y., and Shimamura, H. (1991).Earthquake distribution in the subduction zone off eastern Hokkaido, Japan, deducedfrom ocean-bottom seismographic and land observations. Geophys. J. Int. 105, 693-711.“Life of Fin Whale.” Life of Sea. <http://life-sea.blogspot.com/2011/07/life-of-fin-whale.html>“Ocean Bottom Seismograph Instrument Pool.” NSF. <http://www.obsip.org/index.php/>“Ocean-Bottom Seismometer.” Ocean Instruments. <http://www.whoi.edu/instruments/viewInstrument.do?id=10347>Orcutt, J. A. and Kennett, L. N. (1976). Structure of the East Pacific Rise from an Ocean BottomSeismometer Survey. Geophys. J. R. asir. Society 45, 305-320.Tolstoy, M., Cowen, J. P., Baker, E. T., Fornari, D. J., Rubin, K. H., Shank, T. M., Waldhauser, F.,Bohnenstiehl, D. R., Forsyth, D. W., Holmes, R. C., Love, B., Perfit, M. R., Weekly, R.T., Soule, S. A., and Glazer, B. (2006). A Sea-Floor Spreading Event Captured bySeismometers. Science 314, 1920-1922.Wilcock, W. S. D. (2012). Tracking fin whales in the northeast Pacific Ocean with a seafloorseismic network. Acoustical Society of America 132, 2408-2419.