Provenzano, Giuseppe, Vardy, Mark E. and Henstock, Timothy J. (2018) Decimetric-resolution stochastic inversion of shallow marine seismic reflection data; dedicated strategy and application to a geohazard case study. Geophysical Journal International, 214 (3), 1683-1700. (doi:10.1093/gji/ggy221).
Abstract
Characterisation of the top 10-50 m of the subseabed is key for landslide hazard assessment, offshore structure engineering design and underground gas-storage monitoring. In this paper, we present a methodology for the stochastic inversion of ultra-high-frequency (UHF, 0.2-4.0 kHz) pre-stack seismic reflection waveforms, designed to obtain a decimetric-resolution re- mote elastic characterisation of the shallow sediments with minimal pre-processing and lit- tle a-priori information. We use a genetic algorithm in which the space of possible solutions is sampled by explicitly decoupling the short and long wavelengths of the P-wave velocity model. This approach, combined with an objective function robust to cycle skipping, outperforms a conventional model parametrisation when the ground-truth is offset from the centre of the search domain. The robust P-wave velocity model is used to precondition the width of the search range of the multi-parameter elastic inversion, thereby improving the efficiency in high dimensional parametrizations. Multiple independent runs provide a set of independent results from which the reproducibility of the solution can be estimated. In a real dataset acquired in Finneidfjord, Norway, we also demonstrate the sensitivity of UHF seismic inversion to shallow subseabed anomalies that play a role in submarine slope stability. Thus, the methodology has the potential to become an important practical tool for marine ground model building in spatially heterogeneous areas, reducing the reliance on expensive and time-consuming coring campaigns for geohazard mitigation in marine areas.
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- Faculties (pre 2018 reorg) > Faculty of Natural and Environmental Sciences (pre 2018 reorg) > Ocean and Earth Science (pre 2018 reorg) > Geology & Geophysics (pre 2018 reorg)
Current Faculties > Faculty of Environmental and Life Sciences > School of Ocean and Earth Science > Ocean and Earth Science (pre 2018 reorg) > Geology & Geophysics (pre 2018 reorg)
School of Ocean and Earth Science > Ocean and Earth Science (pre 2018 reorg) > Geology & Geophysics (pre 2018 reorg) - Faculties (pre 2018 reorg) > Faculty of Engineering and the Environment (pre 2018 reorg) > Southampton Marine & Maritime Institute (pre 2018 reorg)
- Faculties (pre 2018 reorg) > Faculty of Natural and Environmental Sciences (pre 2018 reorg) > Ocean and Earth Science (pre 2018 reorg)
Current Faculties > Faculty of Environmental and Life Sciences > School of Ocean and Earth Science > Ocean and Earth Science (pre 2018 reorg)
School of Ocean and Earth Science > Ocean and Earth Science (pre 2018 reorg)
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