Segmentation of the Mid-Atlantic Ridge south of the Azores, based on acoustic classification of TOBI data

Blondel, Philippe

doi:10.1144/gsl.sp.1996.118.01.02

Cited by 27 publications

(41 citation statements)

References 21 publications

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“…This has been confirmed by the theoretical and experimental studies of the last 20 years, presented in Blondel (1996) and Blondel and Murton (1997). Textures can be intuitively described as smooth or rough, small-scale or large-scale, random or organised.…”

Section: Classification With Sidescan Sonarssupporting

confidence: 67%

“…from the backscatter alone) is a combination of too many factors to be unambiguously interpreted (e.g. Blondel, 1996;Blondel and Murton, 1997). A few studies have endeavoured to use the tonal information alone, in some cases with co-registered bathymetry and/or with neural networks, but they were limited to geologically simple terrains, or were of very limited accuracy.…”

Section: Classification With Sidescan Sonarsmentioning

confidence: 99%

“…Their usefulness for sonar images has been assessed in detail (e.g. Blondel, 1996;Blondel, 1999), and only two indices have been retained: entropy and homogeneity. Entropy measures the lack of spatial organization inside the region where the GLCM is computed.…”

Section: Classification With Sidescan Sonarsmentioning

confidence: 99%

“…The other textural parameter, homogeneity, is directly proportional to the amount of local similarities inside the computation window. This parameter was specially modified to ensure its invariance through linear transformations of the grey levels (Blondel, 1996). If the Angle-Varying Gain or Time-Varying Gain are changed during sonar data acquisition, or if the image contrast is changed but the seafloor remains the same, then the modified homogeneity parameter will remain the same.…”

Section: Classification With Sidescan Sonarsmentioning

confidence: 99%

“…Blondel, 1996;Blondel, 1999). It was also shown to detect details invisible to the human eye, however trained, because of its physiological limitations (Blondel, 1996). TexAn is hardwareindependent, and can be used at any stage of processing (or non-processing).…”

Section: Classification With Sidescan Sonarsmentioning

confidence: 99%

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Seabed Classification at Ocean Margins

Blondel

2002

Ocean Margin Systems

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Section: Classification With Sidescan Sonarssupporting

confidence: 67%

Section: Classification With Sidescan Sonarsmentioning

confidence: 99%

Section: Classification With Sidescan Sonarsmentioning

confidence: 99%

Section: Classification With Sidescan Sonarsmentioning

confidence: 99%

Section: Classification With Sidescan Sonarsmentioning

confidence: 99%

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Seabed Classification at Ocean Margins

Blondel

2002

Ocean Margin Systems

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High‐resolution acoustic mapping to understand the ore deposit in the Bayonnaise knoll caldera, Izu‐Ogasawara arc

et al. 2015

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We collected deep‐sea multibeam, side scan, and subbottom profiler data using an autonomous underwater vehicle at the Bayonnaise knoll, a submarine caldera located in the rift zone of the Izu‐Ogasawara arc. We aimed to reveal topographic and geological features and the origin of a hydrothermal field called the Hakurei site in the caldera. We performed seafloor classification by textural analysis using calibrated side‐scan sonar data, which provided an effective means to understand the geology and to highlight potential areas of hydrothermal constructions. The high‐resolution bathymetric map illustrates that the Hakurei hydrothermal field is distributed over a landslide landform in the caldera wall. The distribution of hydrothermal vents indicates that the slip surface has served as a major route of hydrothermal fluids. The radial alignment of chimneys and mounds indicates radial routes of hydrothermal fluid and/or belching along fragile lines in the landslide landform. Various postcaldera activities are inferred including the formation of a lava dome, a pyroclastic cone, and subsequent phreatic explosions. A general volcano‐tectonic structure extending across the caldera in a NW‐SE direction is interpreted as an inferred boundary fault of the North Myojin Rift. Analogous to the Hokuroku basin and land kuroko deposits, it is suggested that the main contributing factor in the formation of kuroko deposits was volcano‐tectonic activity that dominated the margin of the back‐arc rift basin. The intersections between the margin of a rift basin and the surrounding knolls have a high potential for ore‐forming areas.

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Segment‐scale variations in seafloor volcanic and tectonic processes from multibeam sonar imaging, M id‐ A tlantic R idge Rainbow region (35°45′–36°35′N)

Eason

Dunn

Canales

et al. 2016

Geochem. Geophys. Geosyst.

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Along-axis variations in melt supply and thermal structure can lead to significant variations in the mode of crustal accretion at mid-ocean ridges. We examine variations in seafloor volcanic and tectonic processes on the scale of individual ridge segments in a region of the slow spreading Mid-Atlantic Ridge (35845 0 -36835 0 N) centered on the Rainbow nontransform discontinuity (NTD). We use multibeam sonar backscatter amplitude data, taking advantage of multifold and multidirectional coverage from the MARINER geophysical study to create a gridded compilation of seafloor reflectivity, and interpret the sonar image within the context of other data to examine seafloor properties and identify volcanic flow fields and tectonic features. Along the spreading segments, differences in volcanic productivity, faulting, eruption style, and frequency correlate with inferred magma supply. Regions of low magma supply are associated with more widely spaced faults, and larger volcanic flow fields that are more easily identified in the backscatter image. Identified flow fields with the highest backscatter occur near the ends of ridge segments. Their relatively smooth topography contrasts with the more hummocky, cone-dominated terrain that dominates most of the neovolcanic zone. Patches of seafloor with high, moderately high, and low backscatter intensity across the Rainbow massif are spatially correlated with observations of basalt, gabbro and serpentinized peridotite, and sediment, respectively. Large detachment faults have repeatedly formed along the inside corners of the Rainbow NTD, producing a series of oceanic core complexes along the wake of the NTD. A new detachment fault is currently forming in the ridge segment just north of the now inactive Rainbow massif.

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Segmentation of the Mid-Atlantic Ridge south of the Azores, based on acoustic classification of TOBI data

Cited by 27 publications

References 21 publications

Seabed Classification at Ocean Margins

Seabed Classification at Ocean Margins

High‐resolution acoustic mapping to understand the ore deposit in the Bayonnaise knoll caldera, Izu‐Ogasawara arc

Segment‐scale variations in seafloor volcanic and tectonic processes from multibeam sonar imaging, M id‐ A tlantic R idge Rainbow region (35°45′–36°35′N)

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