Abstract
AbstractMass‐transport complexes (MTCs) are often characterized by small‐scale discontinuous internal structure, such as slide blocks, rough interfaces, faults, and truncated strata. Seismic images may not properly resolve such structure because seismic reflections are fundamentally limited in lateral resolution by the source bandwidth. The relatively weak seismic diffractions, instead, encode information on subwavelength‐scale structure, with superior illumination. In this paper, we compare diffraction imaging to conventional, full‐wavefield seismic imaging to characterize MTCs. We apply a seismic diffraction imaging workflow based on plane‐wave destruction filters to two 2D marine multichannel seismic profiles from the Gulf of Cadiz. We observe that MTCs generate a large amount of diffracted energy relative to the unfailed confining sediments. The diffraction images show that some of this energy is localized along existing discontinuities imaged by the full‐wavefield images. We demonstrate that, in combination with full‐wavefield images, diffraction images can be utilized to better discriminate the lateral extent of MTCs, particularly for thin bodies. We suggest that diffraction images may be a more physically correct alternative to commonly used seismic discontinuity attributes derived from full‐wavefield images. Finally, we outline an approach to utilize the out‐of‐plane diffractions generated by the 3D structure of MTCs, normally considered a nuisance in 2D seismic processing. We use a controlled synthetic test and a real‐data example to show that under certain conditions these out‐of‐plane diffractions might be used to constrain the minimum width of MTCs from single 2D seismic profiles.
Highlights
Mass-transport complexes (MTCs) are the deposits of subaqueous mass-movements such as debris flows, slides, and slumps (Mulder & Cochonat, 1996; Piper et al, 1997; Prior et al, 1984; Sawyer et al, 2009)
This suggests that the internal structure of MTC A contains significantly more wavelength and subwavelength-scale discontinuities compared to the unfailed sediments, which can already be seen from the fullwavefield seismic image
Diffraction images can be considered to primarily image small-scale, discontinuous geological structure and have higher lateral resolution compared to full-wavefield seismic images
Summary
Mass-transport complexes (MTCs) are the deposits of subaqueous mass-movements such as debris flows, slides, and slumps (Mulder & Cochonat, 1996; Piper et al, 1997; Prior et al, 1984; Sawyer et al, 2009). Such events pose a significant geohazard to coastal populations from landslide-induced tsunami (Satake, 2012; Tappin et al, 2001) and to seafloor infrastructure such as telecommunications cables and pipelines (Carter et al, 2014; Piper et al, 1999).
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