Multi-Frequency Seafloor Characterization Using Seismic Sources of Opportunity

Nikhil Banda, Philippe Blondel, Mark Burnett, Roy Wyatt

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Abstract

The low frequencies used in seismic surveys mean that seafloor characterization is limited horizontally and vertically. It is possible to use multiple reflections from the seabed to hydrophones on Seismic Support Vessels to measure scattering strengths and geoacoustic properties of seabed areas far from the seismic survey. This can be done by combining lower frequencies (directed toward the seabed and with repeatable beam patterns because of sensor design), providing potential sub-surface penetration and higher frequencies (emitted in all directions, with high inter-pulse variability), directly related to surface properties (slopes, roughness, seabed type). This is demonstrated with results from a shallow-water survey, in which the useful frequency range extends from 100 Hz to 20 kHz. Seismic pulses are used as sources of opportunity, and multiple scattering contributions are corrected for variations in propagation ranges and sizes of scattering patches (related to pulse durations). Twelfth-octave frequency bands give highly accurate information of seabed properties, which can be compared to models or previous measurements. The energy distribution of all measurements can be divided into three equally contributing frequency bands, and their RGB representation enables rapid assessment of seabed properties, identifying geomorphological changes and small-scale topography variations.
Original languageEnglish
Number of pages4
DOIs
Publication statusPublished - 21 Aug 2017
Event23rd European Meeting of Environmental and Engineering Geophysics - Malmö, Sweden
Duration: 3 Sep 20177 Sep 2017
Conference number: 23
http://events.eage.org/en/2017/23rd%20European%20Meeting%20of%20Environmental%20and%20Engineering%20Geophysics

Conference

Conference23rd European Meeting of Environmental and Engineering Geophysics
Abbreviated titleEAGE
CountrySweden
CityMalmö
Period3/09/177/09/17
Internet address

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Keywords

  • seismics
  • seafloor characterisation
  • habitat mapping

ASJC Scopus subject areas

  • Acoustics and Ultrasonics
  • Geophysics
  • Ocean Engineering

Cite this

Banda, N., Blondel, P., Burnett, M., & Wyatt, R. (2017). Multi-Frequency Seafloor Characterization Using Seismic Sources of Opportunity. Paper presented at 23rd European Meeting of Environmental and Engineering Geophysics, Malmö, Sweden. https://doi.org/10.3997/2214-4609.201702015