First arrival stochastic tomography: Automatic background velocity estimation using beam semblances and VFSA

Hu, Chaoshun; Stoffa, Paul L.; McIntosh, K. D.

doi:10.1029/2008gl034776

Cited by 3 publications

(1 citation statement)

References 21 publications

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“…Various methods use different search strategies to locate the spikes and rely on the optimization of different cost functions to satisfy a probabilistic model for the reflectivity (Kormylo and Mendel, 1980;Kaaresen and Taxt, 1998). Other methods proceed to optimize some norm that forces the results to be sparse (Oldenburg et al, 1982;Riel and Berkhout, 1985;Debeye and van Riel, 1990;Sacchi et al, 1994;Hu et al, 2008). Mosegaard and Vestergaard, 1991 address the problem using sparse prior information.…”

Section: Basic Theorymentioning

confidence: 99%

Seismic sparse-layer reflectivity inversion using basis pursuit decomposition

2011

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A basis pursuit inversion of seismic reflection data for reflection coefficients is introduced as an alternative method of incorporating a priori information in the seismic inversion process. The inversion is accomplished by building a dictionary of functions representing reflectivity patterns and constituting the seismic trace as a superposition of these patterns. Basis pursuit decomposition finds a sparse number of reflection responses that sum to form the seismic trace. When the dictionary of functions is chosen to be a wedge-model of reflection coefficient pairs convolved with the seismic wavelet, the resulting reflectivity inversion is a sparse-layer inversion, rather than a sparse-spike inversion. Synthetic tests suggest that a sparse-layer inversion using basis pursuit can better resolve thin beds than a comparable sparse-spike inversion. Application to field data indicates that sparse-layer inversion results in the potentially improved detectability and resolution of some thin layers and reveals apparent stratigraphic features that are not readily seen on conventional seismic sections.

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Section: Basic Theorymentioning

confidence: 99%

Seismic sparse-layer reflectivity inversion using basis pursuit decomposition

2011

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Probabilistic Inverse Theory

Dębski¹

2010

Advances in Geophysics

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An EGF technique to infer the source parameters of a circular crack growing at a variable rupture velocity

de Lorenzo,

Michele

2024

Front. Earth Sci.

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Circular crack models with a constant rupture velocity struggle to effectively model both the amplitude and duration of first P-wave pulses generated by small magnitude seismic events. Assuming a constant rupture velocity is unphysical, necessitating a deceleration phase in the rupture velocity to uphold the causality of the healing process. Moreover, a comprehensive failure model might encompass an initial nucleation phase, typically characterized by an increase of the initial rupture velocity. Studies have demonstrated that quasi-dynamic circular crack models featuring variable rupture velocities can accurately model the shape of the observed first P-wave pulse. Based on these principles, an Empirical Green’s function (EGF) approach was previously formulated to estimate the source parameters of small magnitude earthquakes, called MAIN. In addition to determine the source radius and stress drop, this method also enables the inference of the temporal evolution of rupture velocity. However, this method encounters difficulties when the noise-to-signal ratio in the recordings of smaller earthquakes used as EGF exceeds 5%, a common situation when employing regional-scale recordings of small-magnitude earthquakes as EGF. Through synthetic tests, we demonstrated that, in such instances, the problem of this technique is that the alignment between the onset of P waves of EGF and MAIN is not rightly recovered after the initial inversion step. Consequently, a novel inversion method has been developed to address this issue, enabling the identification of the optimal alignment of P-wave arrivals in EGF and MAIN across all stations. A Bayesian statistical approach is proposed to meticulously investigate the solutions of model parameters and their correlations. Using the new technique on a small magnitude earthquake (ML = 3.3) occurred in Central Italy enabled us to identify the most likely rupture models and examine the issue of correlation among model parameters. Application of Occam’s Razor Principle suggests that, for the investigated event, a circular crack model should be favored over a heterogeneous rupture model.

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First arrival stochastic tomography: Automatic background velocity estimation using beam semblances and VFSA

Cited by 3 publications

References 21 publications

Seismic sparse-layer reflectivity inversion using basis pursuit decomposition

Seismic sparse-layer reflectivity inversion using basis pursuit decomposition

Probabilistic Inverse Theory

An EGF technique to infer the source parameters of a circular crack growing at a variable rupture velocity

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