The Experts below are selected from a list of 6432 Experts worldwide ranked by ideXlab platform

Steven G Schock - One of the best experts on this subject based on the ideXlab platform.

  • Remote Sediment Property Sediment Classification and Property Estimation
    2003
    Co-Authors: Steven G Schock
    Abstract:

    Abstract : The long-term research objective is to develop a cost effective technique for mapping the top 20 meters of Sediment properties using acoustic remote sensing. In previous years, a chirp sonar was developed to provide quantitative, wideband reflection measurements of the seabed with a vertical resolution of 10 cm. Signal processing techniques were developed to estimate vertical profiles of impedance, attenuation and volume scattering coefficients. The Biot model is used to estimate the physical properties of the seabed from the acoustic measurements. The procedures for remotely estimating Sediment properties are being verified using core data and insitu measurements. New signal processing techniques have been developed that allow several sources transmitting simultaneously in different bands to build a wideband FM pulse in the far field. That wideband data is being used to improve the accuracy of the remote acoustic Sediment Property prediction procedures.

  • Remote Sediment Property Estimation from Chirp Data Collected During the Geoclutter Experiment
    2002
    Co-Authors: Steven G Schock
    Abstract:

    Abstract : The long term research objective is to develop a cost effective technique for mapping the top 20 meters of Sediment properties using acoustic remote sensing. In previous years, a chirp sonar was developed to provide quantitative, wideband reflection measurements of the seabed with a vertical resolution of 10 cm. Neural network and fuzzy logic techniques have been used to automatically detect subsurface layer interfaces and to find the boundaries between Sediment layers. Signal processing techniques were developed to estimate vertical profiles of impedance, attenuation and volume scattering coefficients. The procedures for remotely estimating Sediment properties are being verified using core data and insitu measurements. New signal processing techniques have been developed that allow several sources transmitting simultaneously in different bands to build a wideband FM pulse in the far field. That wideband data is being used to improve the accuracy of the remote acoustic Sediment Property prediction procedures.

  • Remote Sediment Property from Chirp Data Collected During ASIAEX
    2001
    Co-Authors: Steven G Schock
    Abstract:

    Abstract : The long term research objective is to develop a cost effective technique for mapping the top 20 meters of Sediment properties using acoustic remote sensing. In previous years, a chirp sonar was developed to provide quantitative, wideband reflection measurements of the seabed with a vertical resolution of 10 cm. Neural network and fuzzy logic techniques have been used to automatically detect subsurface layer interfaces and to find the boundaries between Sediment layers. Signal processing techniques were developed to estimate vertical profiles of impedance, attenuation and volume scattering coefficients. The procedures for remotely estimating Sediment properties are being verified using core data and insitu measurements. New signal processing techniques have been developed that allow several sources transmitting simultaneously in different bands to build a wideband FM pulse in the far field. That wideband data is being used to improve the accuracy of the remote acoustic Sediment Property prediction.

  • Techniques for estimating Sediment properties from chirp sonar data
    The Journal of the Acoustical Society of America, 2001
    Co-Authors: Steven G Schock
    Abstract:

    The chirp sonar is a towed wideband FM reflection profiler developed to collect normal incidence reflection data suitable for Sediment Property inversions; the sonar also generates detailed reflection profiles of the seabed. The chirp sonar system transmits FM pulses with high time‐bandwidth products to attain high pulse energy; consequently, the acoustic data have a high signal‐to‐ambient‐noise ratio after correlation processing. The vertical resolution of the images is about 1 cm when transducer bandwidth is approximately 40 kHz. Data processing methods have been developed to automatically map the locations of Sediment layer interfaces, and to estimate compressional wave attenuation, acoustic impedance, and compressional wave velocity of Sediment layers using normal incidence FM reflection data. The height of sand ripples and the phase dispersion of compressional waves can also be measured from the acoustic imagery. Field data collected by other investigators during the High Frequency Acoustics DRI expe...

  • Remote Seabed Sediment Classification and Sediment Property Estimation Using High Resolution Reflection Profiles
    1999
    Co-Authors: Steven G Schock
    Abstract:

    Abstract : The long term research objective is to develop a cost effective technique for mapping the top 20 meters of Sediment properties using acoustic remote sensing. In previous years, a chirp sonar was developed to provide quantitative, wideband reflection measurements of the seabed with a vertical resolution of 10 cm. Neural network and fuzzy logic techniques have been used to automatically detect subsurface layer interfaces and to find the boundaries between Sediment layers. Signal processing techniques were developed to estimate vertical profiles of impedance and attenuation. The procedures for remotely estimating Sediment properties are being verified using core data and in situ measurements. New signal processing techniques have been developed that allow several sources transmitting simultaneously in different bands to build a wideband FM pulse in the far field. That wideband data is being used to improve the accuracy of the Sediment classification procedures and to provide the capability of measuring phase dispersion.

Claudia Schröder-adams - One of the best experts on this subject based on the ideXlab platform.

  • Highstand transport of coastal sand to the deep ocean: A case study from Fraser Island, southeast Australia
    Geology, 2008
    Co-Authors: Ron Boyd, Kevin Ruming, Marianne Sandstrom, Ian Goodwin, Claudia Schröder-adams
    Abstract:

    Deep-water sands form a new frontier for marine geology and petroleum exploration, but how does sand reach the deep sea? Existing geological models predict that deep-water sands are mainly supplied from rivers during times of low sea level, or by incision of canyons into the shelf to tap river or longshore-transport sand sources. Here, we demonstrate that at high sea level, southeast Australian deep-water sands are delivered by a wave-driven coastal transport system, interacting with estuarine ebb tidal flows, that transports sand over the shelf edge at a change in margin orientation. Discovery of this new process results from an investigation that combines multibeam acoustic, microfaunal, zircon and luminescence dating, oceanographic, Landsat, remotely operated vehicle, and Sediment Property methods. Our longshore transport–driven model is capable of forecasting new locations for deep-water sand deposits in a predictive paleoclimatic and paleotectonic setting.

Anthony P. Lyons - One of the best experts on this subject based on the ideXlab platform.

  • X-ray tomographic analysis of Sediment macrostructure in Eckernförde Bay, western Baltic Sea
    Geo-Marine Letters, 1996
    Co-Authors: T.h. Orsi, A.l. Anderson, Anthony P. Lyons
    Abstract:

    X-ray computed tomography analysis of Sediment cores from Eckernforde Bay (western Baltic Sea) indicates that the primary macrostructures and sources of physical Property variability are feeding pockets and laminae. Burrowing produces easily discernible macrostructures, yet has a nominal effect overall on Sediment Property variability. Grain-size distribution is a dominant parameter determining the Sediment macrostructure—physical Property relationship: the largest variation in Sediment properties was associated with sandy Sediment and the smallest with muds. However, equally significant is the sorting or spatial distribution of grains within a particular Sediment horizon, i.e., whether spatially uniform or patchy.

B. Bohling - One of the best experts on this subject based on the ideXlab platform.

  • Permeability of Sands in the Coastal Areas of the Southern Baltic Sea: Mapping a Grain-size Related Sediment Property
    Aquatic Geochemistry, 2003
    Co-Authors: S. Forster, B. Bobertz, B. Bohling
    Abstract:

    We compared measurements of vertical permeability, grain size distribution, and porosity from sandy surface Sediments in the southern Baltic Sea. Using this information we constructed maps reflecting the permeability within the study area. We found that the formula suggested by Krumbein and Monk (1942) overestimates measured permeabilites on average by a factor 2.6 for the area investigated. The results of a formula including porosity, as in the Carman-Kozeny relation (Carman, 1937), deviated even more from our observations. Vertical heterogeneity of the Sediments between 0–10 cm depth and the content of fine particulate material were likely responsible for this phenomenon. Our findings suggest that Sediments, classified by averagegrain size based nomenclature as sands, cannot generally be assumed to be highly permeable. Nevertheless, maps constructed mirror the distribution of the average grain size in two data sets we used. For the shallow southern Baltic and an assumed threshold for permeability-effects of2.5 × 10^-12 m^2, wecalculate >41% of the sea floor to be permeable. An additional 27% may be permeable, but were excluded from calculations due to poor sorting.

  • permeability of sands in the coastal areas of the southern baltic sea mapping a grain size related Sediment Property
    Aquatic Geochemistry, 2003
    Co-Authors: S. Forster, B. Bobertz, B. Bohling
    Abstract:

    We compared measurements of vertical permeability, grain size distribution, and porosity from sandy surface Sediments in the southern Baltic Sea. Using this information we constructed maps reflecting the permeability within the study area. We found that the formula suggested by Krumbein and Monk (1942) overestimates measured permeabilites on average by a factor 2.6 for the area investigated. The results of a formula including porosity, as in the Carman-Kozeny relation (Carman, 1937), deviated even more from our observations. Vertical heterogeneity of the Sediments between 0–10 cm depth and the content of fine particulate material were likely responsible for this phenomenon.

Ron Boyd - One of the best experts on this subject based on the ideXlab platform.

  • Highstand transport of coastal sand to the deep ocean: A case study from Fraser Island, southeast Australia
    Geology, 2008
    Co-Authors: Ron Boyd, Kevin Ruming, Marianne Sandstrom, Ian Goodwin, Claudia Schröder-adams
    Abstract:

    Deep-water sands form a new frontier for marine geology and petroleum exploration, but how does sand reach the deep sea? Existing geological models predict that deep-water sands are mainly supplied from rivers during times of low sea level, or by incision of canyons into the shelf to tap river or longshore-transport sand sources. Here, we demonstrate that at high sea level, southeast Australian deep-water sands are delivered by a wave-driven coastal transport system, interacting with estuarine ebb tidal flows, that transports sand over the shelf edge at a change in margin orientation. Discovery of this new process results from an investigation that combines multibeam acoustic, microfaunal, zircon and luminescence dating, oceanographic, Landsat, remotely operated vehicle, and Sediment Property methods. Our longshore transport–driven model is capable of forecasting new locations for deep-water sand deposits in a predictive paleoclimatic and paleotectonic setting.