Characterisation of shallow overpressure in consolidating submarine slopes via seismic full waveform inversion
| Autor: | Giuseppe Provenzano, Timothy J. Henstock, Antonis Zervos, Mark E. Vardy |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
010504 meteorology & atmospheric sciences
Effective stress Geology 010502 geochemistry & geophysics Geotechnical Engineering and Engineering Geology 01 natural sciences Overpressure law.invention Factor of safety Pore water pressure law Slope stability Earth and Planetary Sciences (miscellaneous) Hydrostatic equilibrium Seismogram Seabed Seismology 0105 earth and related environmental sciences |
| Popis: | Pore pressures higher than hydrostatic correspond to localized reductions of the level of stress required to induce lateral mass movement in a slope, and therefore play a key role in preconditioning submarine landsliding. In this paper, we investigate whether multi-channel seismic reflection data can be used to infer potentially destabilizing pore-pressure levels at a resolution and sensitivity useful for in-situ slope stability characterization. We simulate the continuous deposition of sediment on consolidating slopes in two scenarios, with combinations of sedimentation rate and permeability distribution leading to disequilibrium compaction. Ultra-high-frequency (UHF; 0.2–2.5 kHz) seismic reflection data are computed for each model and a stochastic full waveform inversion (FWI) method is used to retrieve the sub-seabed properties from the computed seismograms. These are then interpreted as time–depth variations in the effective stress (σʹ) regime, and therefore local overpressure ratio and factor of safety, using a combination of p-wave velocity to σʹ transforms. The results demonstrate that multi-channel UHF seismic data can provide valuable constraints on the distribution of physical properties in the top 50 m below seabed at a sub-metric scale, and with a sensitivity useful to infer destabilizing excess pore pressure levels. Thematic collection: This article is part of the Measurement and monitoring collection available at: https://www.lyellcollection.org/cc/measurement-and-monitoring |
| Databáze: | OpenAIRE |
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