Preprints
https://doi.org/10.5194/egusphere-2022-733
https://doi.org/10.5194/egusphere-2022-733
09 Sep 2022
 | 09 Sep 2022

Seismic amplitude response to internal heterogeneity of mass-transport deposits

Jonathan Ford, Angelo Camerlenghi, Francesca Zolezzi, and Marilena Calarco

Abstract. Compared to unfailed sediments, mass-transport deposits are often characterised by a low-amplitude response in single-channel seismic reflection images. This ‘acoustic transparency’ amplitude signature is widely used to delineate mass-transport deposits and is conventionally interpreted as a lack of coherent internal reflectivity due to a loss of preserved internal structure caused by mass-transport processes. In this study we examine the variation in the single-channel seismic response with changing heterogeneity using synthetic 2-D elastic seismic modelling. We model the internal structure of mass-transport deposits as a two-component random medium, using the lateral correlation length (ax) as a proxy for the degree of internal deformation, whilst maintaining approximately constant internal reflectivity with increasing deformation. For a controlled single-source synthetic model a reduction in observed amplitude with reduced ax is consistently observed across a range of vertical correlation lengths (az). For typical AUV sub-bottom profiler acquisition parameters, in a simulated mass-transport deposit with realistic elastic and geostatistical properties, we find that when ax ≈ 1 m, recorded seismic amplitudes are, on average, reduced by ∼ 15 % relative to unfailed sediments (ax ≫ 103 m). We also observe that deformation significantly larger than core-scale (ax > 0.1 m) can generate a significant amplitude decrease. These synthetic modelling results should discourage interpretation of the internal structure of mass-transport deposits based on seismic amplitudes alone, as ‘acoustically transparent’ mass-transport deposits may still preserve coherent, metre-scale internal structure. In addition, the minimum scale of heterogeneity required to produce a significant reduction in seismic amplitudes is likely much larger than the diameter of sediment cores, meaning that ‘acoustically transparent’ mass-transport deposits may still appear well-stratified and undeformed at core-scale.

Journal article(s) based on this preprint

22 Feb 2023
Seismic amplitude response to internal heterogeneity of mass-transport deposits
Jonathan Ford, Angelo Camerlenghi, Francesca Zolezzi, and Marilena Calarco
Solid Earth, 14, 137–151, https://doi.org/10.5194/se-14-137-2023,https://doi.org/10.5194/se-14-137-2023, 2023
Short summary

Jonathan Ford et al.

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-733', Jasper Moernaut, 21 Sep 2022
  • CC1: 'Comment on egusphere-2022-733', Martino Foschi, 17 Oct 2022
  • EC1: 'Comment on egusphere-2022-733', Simone Pilia, 18 Oct 2022
    • AC1: 'Reply on EC1', Jonathan Ford, 22 Nov 2022
  • RC2: 'Comment on egusphere-2022-733', Martino Foschi, 22 Oct 2022

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-733', Jasper Moernaut, 21 Sep 2022
  • CC1: 'Comment on egusphere-2022-733', Martino Foschi, 17 Oct 2022
  • EC1: 'Comment on egusphere-2022-733', Simone Pilia, 18 Oct 2022
    • AC1: 'Reply on EC1', Jonathan Ford, 22 Nov 2022
  • RC2: 'Comment on egusphere-2022-733', Martino Foschi, 22 Oct 2022

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Jonathan Ford on behalf of the Authors (22 Nov 2022)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (24 Nov 2022) by Simone Pilia
RR by Jasper Moernaut (24 Nov 2022)
RR by Martino Foschi (14 Jan 2023)
ED: Publish as is (20 Jan 2023) by Simone Pilia
ED: Publish as is (06 Feb 2023) by CharLotte Krawczyk (Executive editor)
AR by Jonathan Ford on behalf of the Authors (07 Feb 2023)  Manuscript 

Journal article(s) based on this preprint

22 Feb 2023
Seismic amplitude response to internal heterogeneity of mass-transport deposits
Jonathan Ford, Angelo Camerlenghi, Francesca Zolezzi, and Marilena Calarco
Solid Earth, 14, 137–151, https://doi.org/10.5194/se-14-137-2023,https://doi.org/10.5194/se-14-137-2023, 2023
Short summary

Jonathan Ford et al.

Model code and software

Seismic amplitude response to internal heterogeneity of mass-transport deposits Ford, Jonathan; Camerlenghi, Angelo; Zolezzi, Francesca; Calarco, Marilena https://doi.org/10.5281/zenodo.6949300

Jonathan Ford et al.

Viewed

Total article views: 488 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
367 102 19 488 41 4 5
  • HTML: 367
  • PDF: 102
  • XML: 19
  • Total: 488
  • Supplement: 41
  • BibTeX: 4
  • EndNote: 5
Views and downloads (calculated since 09 Sep 2022)
Cumulative views and downloads (calculated since 09 Sep 2022)

Viewed (geographical distribution)

Total article views: 462 (including HTML, PDF, and XML) Thereof 462 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 07 Oct 2023
Download

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Short summary
Submarine landslides commonly appear as low-amplitude zones in seismic data. Previous studies have attributed this to a lack of preserved internal structure. We use seismic modelling to show that an amplitude reduction can be generated even when there is still metre-scale internal structure, by simply deforming the bedding. This has implications for interpreting failure type, for core-seismic correlation and for discriminating landslides from other "transparent" phenomena such as free gas.