A full wave solution for propagation in multilayered viscoelastic media with application to Gaussian beam reflection at fluid–solid interfaces

Schmidt, Henrik; Jensen, Finn B.

doi:10.1121/1.392050

Cited by 209 publications

(71 citation statements)

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“…The generated signals included various pulse shapes and lengths, however, for the data of interest to this chapter, no dependence on pulse shape or length was found. An extensive set of geoacoustic measurements were made at the experimental site (the particulars of the geoacoustic data are discussed in detail in the following section, section 5.1) and the buried hydrophone array data were compared with the SAFARI [Schmidt et al (1985)] model using the measured sediment geoacoustic properties as inputs.…”

Section: Discussionmentioning

confidence: 99%

The effects of sediment porosity on acoustic reflection and transmission at the seafloor

Holland¹

1992

The Journal of the Acoustical Society of America

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(Manu2OThe Biot theory of propagation in a porous medium provides a mathematical framwork for studying acoustic interaction with the seafloor. The theory considers the two-phase porous nature of marine sediments in contrast to the classical models of wave propagation in the seafloor that consider marine sediments as an extended single-phase fluid or solid.A boundary value problem is set up and olved for a line source in a fluid medium above a ooro-vi r'oelastic halfspace. Expressions for the reflected nd transmitted field are given in integral form and asymptotic expansions in the high-frequency, far-field limit.A set of simultaneous equations is solved to give plane wave reflection and transmission (Type I, Type II and shear wave) coefficients.These equations also yield the Scholte, pseudo-Scholte and pseudo-Rayleigh wave phase velocities and attenuations.The plan wave coefficien and the surface wave velocities and attenuations are compared with commensurate quantities from the single-phase theories.A number of recent experiments of high frequency transmission through a water-sand interface have indicated anomalously high transmitted energy at angles near the critical angle. The Type II wave (predicted by Blot theory but not the single-phase theories) was suspected as a possible reason for the anomalies.Data from one of the experiments are examined sediment porosity, seafloor, reflection, transmission, porous medium, acoustic interaction, two-phase, water-sand interface, Biot theory

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Section: Discussionmentioning

confidence: 99%

The effects of sediment porosity on acoustic reflection and transmission at the seafloor

Holland¹

1992

The Journal of the Acoustical Society of America

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“…Despite an inherent loss of horizontal resolution, such an assumption is acceptable in shallow, recent and weakly tectonised sediments, and allows for the forward model to be computed using an analytic fast solution in the plane wave domain within a reasonable computational cost (Fuchs & Müller, 1971). The program chosen to compute the pressure seismograms is the Ocean Acoustics and Seismic Exploration Synthesis from MIT (Schmidt & Jensen, 1985;Schmidt & Tango, 1986. ), which addresses the reflectivity modelling in an efficient and accurate way for the frequency-wavenumber range of interest.…”

Section: Full Marine Seismogram Modelling In the Varying Streamer Depmentioning

confidence: 99%

Pre-stack full waveform inversion of ultra-high-frequency marine seismic reflection data

Provenzano

Vardy

Henstock

2017

Geophysical Journal International

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SUMMARYThe full waveform inversion (FWI) of seismic reflection data aims to reconstruct a detailed physical properties model of the subsurface, fitting both the amplitude and traveltime of the reflections generated at physical discontinuities in the propagation medium. Unlike reservoirscale seismic exploration, where seismic inversion is a widely adopted remote characterisation tool, ultra high frequency (UHF, 0.2-4.0 kHz) multi-channel marine reflection seismology is still most often limited to a qualitative interpretation of the reflections' architecture. Here we propose an elastic full waveform inversion methodology, custom-tailored for pre-stack UHF marine data in vertically heterogeneous media to obtain a decimetric-scale distribution of Pimpedance, density and Poisson's ratio within the shallow sub-seabed sediments. We address the deterministic multi-parameter inversion in a sequential fashion. The complex trace instantaneous phase is first inverted for the P-wave velocity to make-up for the lack of low-frequency in the data and reduce the non-linearity of the problem. This is followed by a short-offset Pimpedance optimisation and a further step of full offset range Poisson's ratio inversion. Provided that the seismogram contains wide reflection angles (> 40 degrees), we show that it is possible to invert for density and decompose a-posteriori the relative contribution of P-wave velocity and density to the P-impedance. A broad range of synthetic tests is used to prove the potential of the methodology and highlights sensitivity issues specific to UHF seismic. An example application to real data is also presented. In the real case, trace normalisation is applied to minimise the systematic error deriving from an inaccurate source wavelet estimation. G. Provenzano et al.The inverted model for the top 15 meters of the sub-seabed agrees with the local lithological information and core-log data. Thus we can obtain a detailed remote characterisation of the shallow sediments using a multi-channel sub-bottom profiler within a reasonable computing cost and with minimal pre-processing. This has the potential to reduce the need of extensive geotechnical coring campaigns.

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“…The difficulty has not been in general that the necessary tools to do this modeling are unavailable. For instance, Schmidt's Fast Field algorithm, SAFARI [2], has proven to be a very capable package for solving propagation problems in a complex seismo-acoustic environment such as is presented by the deep Arctic. The difficulty has been that very little work has been done to obtain measurements of the starting parameters crucial to computing this propagation accurately, i.e., the elastic parameters of the ice canopy-compressional and shear wave bulk velocities and attenuation factors.…”

Section: Motivationmentioning

confidence: 99%

“…Stein [14] used a specialized computational routine to solve the P-SV system of equations for the floating plate numerically; however Schmidt [2] has developed a much more flexible tool to apply to this problem, the Seismo-Acoustic Fast…”

Section: Numerical Solutionsmentioning

confidence: 99%

Observation and inversion of seismo-acoustic waves in a complex Artic ice environment

Miller¹

1990

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A full wave solution for propagation in multilayered viscoelastic media with application to Gaussian beam reflection at fluid–solid interfaces

Cited by 209 publications

References 0 publications

The effects of sediment porosity on acoustic reflection and transmission at the seafloor

The effects of sediment porosity on acoustic reflection and transmission at the seafloor

Pre-stack full waveform inversion of ultra-high-frequency marine seismic reflection data

Observation and inversion of seismo-acoustic waves in a complex Artic ice environment

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