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IS-BILAT-Mobilitet Norge-USA /Canada

Inversion of seismo-acoustic data for elastic properties of the ocean bottom

Awarded: NOK 19,000

In the ocean, remote sensing of acoustic waves is the primary means to determine physical characteristics of the sea bed materials and the sub-bottom structure. Examples of remote sensing applications span a broad spectrum, including geotechnical site in spections for cable and pipe laying and installations of sea bed platforms; mapping and assessment of sea bed habitats; geophysical exploration for oil and gas; and naval applications in mine hunting. Interpretation of the acoustic data requires an inver sion of the measured data based on a geoacoustic model of the ocean environment that is used to describe the interaction of sound with the ocean bottom. The overall research theme of this proposal is to continue development and application of inversion m ethods to estimate ocean bottom properties from acoustic field data measured in the water column in ocean acoustic experiments or seismic surveys. Our specific interest is in using the information in reflection coefficient versus angle data and the dispe rsion of seismo-acoustic interface waves to estimate the variation of shear wave speeds with depth in sea bottom sediments. The shear wave profile provides a measure of the shear modulus of the sediment, and is resolved on a finer spatial scale, consisten t with the shorter wavelength of the shear waves. The approaches that are the focus of this research proposal are not conventionally applied in seismic interpretations, and our research is designed to study the quality of the information obtained from a nalysis of the data and compare the results with those obtained from conventional methods. The visit proposed in this application will continue a research collaboration with Dr. Hefeng Dong that extends the seismo-acoustic inversion methods from Dr. Cha pman's research in ocean acoustics at the University of Victoria (UVic) to new applications with Norwegian data from seismic experiments designed to record interface waves.

Funding scheme:

IS-BILAT-Mobilitet Norge-USA /Canada