A Formalism for Acoustical Traveltime Tomography in Heterogeneous Anisotropic Media

Song, Lin-Ping; Zhang, Shuyi; Hao-wu, Liu; Chun, Sha; Song, Zheng-zong

doi:10.1007/978-1-4615-5339-7_198

Cited by 3 publications

(2 citation statements)

References 5 publications

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“…Regarding the inversion process, the main difficulty arises from the trade-off between velocity heterogeneity and anisotropy (e.g., Bezada et al, 2014). To the best of our knowledge, Stewart (1988) was the first to propose an inversion algorithm, specifically for the recovery of Thomsen's parameters in a weakly anisotropic VTI medium. Other authors have produced inversion algorithms for different formulations such as azimuthal anisotropy (e.g., Eberhart-Phillips and Henderson, 2004;Dunn et al, 2005) or a 3-D TTI medium (e.g., Zhou and Greenhalgh, 2008).…”

Section: Anisotropy In Seismic Inversion Methodsmentioning

confidence: 99%

Anisotropic P-wave travel-time tomography implementing Thomsen's weak approximation in TOMO3D

Meléndez¹,

Tejero²,

Sallarès³

et al. 2019

Solid Earth

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Abstract. We present the implementation of Thomsen's weak anisotropy approximation for vertical transverse isotropy (VTI) media within TOMO3D, our code for 2-D and 3-D joint refraction and reflection travel-time tomographic inversion. In addition to the inversion of seismic P-wave velocity and reflector depth, the code can now retrieve models of Thomsen's parameters (δ and ε). Here, we test this new implementation following four different strategies on a canonical synthetic experiment in ideal conditions with the purpose of estimating the maximum capabilities and potential weak points of our modeling tool and strategies. First, we study the sensitivity of travel times to the presence of a 25 % anomaly in each of the parameters. Next, we invert for two combinations of parameters (v, δ, ε and v, δ, v⊥), following two inversion strategies, simultaneous and sequential, and compare the results to study their performance and discuss their advantages and disadvantages. Simultaneous inversion is the preferred strategy and the parameter combination (v, δ, ε) produces the best overall results. The only advantage of the parameter combination (v, δ, v⊥) is a better recovery of the magnitude of v. In each case, we derive the fourth parameter from the equation relating ε, v⊥ and v. Recovery of v, ε and v⊥ is satisfactory, whereas δ proves to be impossible to recover even in the most favorable scenario. However, this does not hinder the recovery of the other parameters, and we show that it is still possible to obtain a rough approximation of the δ distribution in the medium by sampling a reasonable range of homogeneous initial δ models and averaging the final δ models that are satisfactory in terms of data fit.

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Section: Anisotropy In Seismic Inversion Methodsmentioning

confidence: 99%

Anisotropic P-wave travel-time tomography implementing Thomsen's weak approximation in TOMO3D

Meléndez¹,

Tejero²,

Sallarès³

et al. 2019

Solid Earth

View full text Add to dashboard Cite

show abstract

“…Thomsen's parameters are by far the most common and convenient combinations of stiffness tensor elements used in seismic anisotropy modelling (Tsvankin, 1996;Thomsen and Anderson, 2015). Applications of simpler approximations exist, as is the case of elliptical symmetry (Song et al, 1998;Giroux and Gloaguen, 2012), as well as others that assume the most general anisotropic model (Zhou and Greenhalgh, 2008).…”

Section: Introductionmentioning

confidence: 99%

Anisotropic P-wave traveltime tomography implementing Thomsen's weak approximation in TOMO3D

Meléndez¹,

Jiménez²,

Sallarès³

et al. 2019

Preprint

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Abstract. We present the implementation of Thomsen's weak anisotropy approximation for VTI media within TOMO3D, our code for 2-D and 3-D joint refraction and reflection traveltime tomographic inversion. In addition to the inversion of seismic P-wave velocity and reflector depth, the code can now retrieve models of the Thomsen's parameters δ and ε. Here we test this new implementation following four different strategies on a canonical synthetic experiment. First, we study the sensitivity of traveltimes to the presence of a 25 % anomaly in each of the parameters. Next, we invert for two combinations of parameters, (v, δ, ε) and (v, δ, v⟂), following two inversion strategies, simultaneous and sequential, and compare the results to study their performances and discuss their advantages and disadvantages. Simultaneous inversion is the preferred strategy and the parameter combination (v, δ, ε) produces the best overall results. The only advantage of the parameter combination (v, δ, v⟂) is a better recovery of the magnitude of v. In each case we derive the fourth parameter from the equation relating ε, v⟂ and v. Recovery of v, ε and v⟂ is satisfactory whereas δ proves to be impossible to recover even in the most favorable scenario. However, this does not hinder the recovery of the other parameters, and we show that it is still possible to obtain a rough approximation of δ distribution in the medium by sampling a reasonable range of homogeneous initial δ models and averaging the final δ models that are satisfactory in terms of data fit.

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Mapping an underground rock mass by anisotropic acoustical transmission tomography

Song

Hao-wu²,

Chun

et al. 1998

Ultrasonics

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A Formalism for Acoustical Traveltime Tomography in Heterogeneous Anisotropic Media

Cited by 3 publications

References 5 publications

Anisotropic P-wave travel-time tomography implementing Thomsen's weak approximation in TOMO3D

Anisotropic P-wave travel-time tomography implementing Thomsen's weak approximation in TOMO3D

Anisotropic P-wave traveltime tomography implementing Thomsen's weak approximation in TOMO3D

Mapping an underground rock mass by anisotropic acoustical transmission tomography

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