Probabilistic Seismic Inversion for Shallow Site Characterization on the Hydrate Ridge Area

Site characterization with 3D elastic full-waveform tomography

Geophysics ◽

10.1190/geo2017-0571.1 ◽

2018 ◽

Vol 83 (5) ◽

pp. R389-R400 ◽

Cited By ~ 13

Author(s):

Trung Dung Nguyen ◽

Khiem T. Tran

Keyword(s):

Field Data ◽

Wave Equations ◽

Site Characterization ◽

Standard Penetration Test ◽

Seismic Inversion ◽

Waveform Analysis ◽

Staggered Grid ◽

Model Parameters ◽

Optimization Approach ◽

Full Waveform

We have developed a 3D elastic full-waveform inversion (FWI) method for geotechnical site characterization. The method is based on a solution of 3D elastic-wave equations for forward modeling to simulate wave propagation and a local optimization approach based on the adjoint-state method to update the model parameters. The staggered-grid finite-difference technique is used to solve the wave equations together with implementation of the perfectly matched layer condition for boundary truncation. Seismic wavefields are acquired from geophysical testing using sensors and sources located in uniform 2D grids on the ground surface, and they are then inverted for the extraction of 3D subsurface wave velocity structures. The capability of the presented FWI method is tested on synthetic and field data sets. The inversion results from synthetic data indicate the ability of characterizing laterally variable low- and high-velocity layers. Field experimental data were collected using 96 receivers and a propelled energy generator to induce seismic wave energy. The field data result indicates that the waveform analysis was able to delineate variable subsurface soil layers. The seismic inversion results are generally consistent with invasive standard penetration test [Formula: see text]-values, including identification of a low-velocity zone.

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Seismic Attributes and Acoustic Inversion for Shallow Marine Slope Stratigraphy Analysis

10.4043/31102-ms ◽

2021 ◽

Author(s):

Jungrak Son ◽

Rebecca Boon ◽

Julien Kuhn de Chizelle

Keyword(s):

Signal Processing ◽

Site Characterization ◽

Seismic Attributes ◽

Offshore Structures ◽

Seismic Inversion ◽

Shallow Marine ◽

Time Domain Data ◽

Geological Features ◽

Marine Site ◽

The Hilbert Transform

Abstract Geophysical seismic surveys have been used in marine site characterization for subsea engineering and the design of offshore structures. Signal processing plays a key role in obtaining seismic attributes from observed seismic data to identify subsurface geological features within complex shallow sediments. Instantaneous amplitude, phase, and frequency are the most widely used seismic attributes to indicate geological features, but those time-domain data are too limited to define an accurate subsurface model in depth. Therefore, seismic inversion is also required to generate additional geospatial subsurface model information to aid in shallow stratigraphy interpretation. In this paper, we applied both geophysical signal processing and stochastic seismic inversion to a high-resolution multichannel seismic dataset from the Eastern North American Margin (ENAM). Seismic attributes from the Hilbert transform and inversion modeling results (acoustic impedance and modeling uncertainty) were integrated to define better geological horizons and discontinuities. The results show the integrated geophysical subsurface models can support seismic interpretation and improve shallow marine site characterization.

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