Multibeam backscatter as a tool for sea-floor characterization and identification of oil spills in the Galicia Bank

Abstract

This study is focused on the potential of using the multibeam acoustic backscatter both for seafloor characterization of the Galicia Bank and for identification of seabottom oil spills. An extended multibeam data set was acquired during the RG-1 and RG-2 surveys aboard RV Hespérides in 2003 for the geological and geophysical characterization of the Galicia Bank, where the oil tanker Prestige wreck is located. 3-D images have been made by integrating bathymetry and backscatter data. Multibeam data have been additionally supported by gravity core information in order to correlate sea-floor acoustic backscatter with the surficial sediments and their physical properties. The major factors that seem to control the zonation of the backscatter intensity images are (i) the type of the sedimentary processes (gravitational, turbiditic, hemipelagic), which control at same time, the grain size distribution, and (ii) the seabottom morphologies, such as basement outcrops. However, there are some backscatter halos that can not be explained by these processes. In the backscatter maps, the bow and stern of the Prestige wreck are clearly marked by a high-backscatter intensity anomaly, whose existence is discussed.

Recommendations for improved and coherent acquisition and processing of backscatter data from seafloor-mapping sonars

“…Substantial efforts have been made in trying to obtain seafloor type or physical characteristics from the measurement of the backscatter level (e.g., Brown and Blondel 2009;De Moustier and Matsumoto 1993;Kloser et al 2010;Lamarche et al 2011;McGonigle and Collier 2014;Preston et al 2001), in many cases according to its angle dependence (Haniotis et al 2015). Some original applications include recognition and mapping algae (McGonigle et al 2011), oil spills (Medialdea et al 2008), or hydrothermal vents and seeps (Durand et al 2006;Klaucke et al 2008).…”

“…Gutierrez et al 2015;Lucieer et al 2015;Medialdea et al 2008). This potential, in parallel with the need for objective and quantitative information on the seafloor from remotely-sensed data has resulted in a line of research and development that has developed acquisition, processing and interpretation of the backscatter signal as quantitative tools for geological and environmental purposes (Lurton and Lamarche 2015).…”

Riverbed sediment classification using multi-beam echo-sounder backscatter data

“…There might exist different ways to approach this goal. One can, for instance, rely on the previous work, 3,4,8,9,37 where the estimated i 's can directly be associated with the seafloor mean grain size. An alternative, followed in this contribution, is to use the results from the core analysis for comparison and to perform a correlation analysis afterward.…”

Assessment of Multibeam Backscatter Texture Analysis for Seafloor Sediment Classification

“…bathymetry) and acoustic backscatter (i.e. intensity returns) is vital for sediment and habitat types prediction (De Falco et al, 2010;Medialdea et al, 2008;Sutherland et al, 2007). Backscatter returns from MBES is one of the potential dataset from acoustic technique that is seen to consist of important acoustic scattering information of the sediment types and offers huge possibility of remote identification of seafloor as well as proxy for habitat classes.…”