Detection of fault structure under a near-surface low velocity layer by seismic tomography: synthetics studies

Sanny, Teuku Abdullah; Sassa, Koichi

doi:10.1016/0926-9851(96)00013-4

Cited by 12 publications

(3 citation statements)

References 4 publications

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“…A nullspace substantially contracts if an examined object is accessible for taking measurements from three edges at least [12]. This was confirmed in practice by Sanny and Sassa [13].…”

Section: Introductionmentioning

confidence: 55%

Multigrid Regularized Image Reconstruction for Limited-Data Tomography

Zdunek¹

2007

CMST

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Limited-data tomography, to which electromagnetic geotomography belongs, is analyzed in this paper. In this technique, a discrete forward projection model may be expressed by a rank-deficient system of linear equations whose the nullspace is non-trivial. This means that some image components may fall into the nullspace, and hence the minimal-norm least-square solution, to which many image reconstructions methods converge, may be different from the true one. The Algebraic Reconstruction Technique (ART), Simultaneous Iterative Reconstruction Technique (SIRT), or Conjugate Gradients Least Squares (CGLS) are examples of such methods. In this paper, we deal with the question of how to partially recover the missing image components. First, we analyze the advantages of using the iterative Tikhonov regularization and the Maximum A Posteriori (MAP) algorithm with Gibbs prior. Then, we conclude that the missing (nullspace) image components can be partially recovered if the MAP algorithm is implemented through a multigrid technique. The results, which are presented for synthetic noise-free and noisy data, demonstrate the validity of our assumption. The problem of estimating the regularization and scaling parameters in the MAP algorithm is also addressed.

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“…A nullspace substantially contracts if an examined object is accessible for taking measurements from three edges at least [12]. This was confirmed in practice by Sanny and Sassa [13].…”

Section: Introductionmentioning

confidence: 55%

Multigrid Regularized Image Reconstruction for Limited-Data Tomography

Zdunek¹

2007

CMST

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“…Tomography is a reconstruction of a geometric object from the observed physical parameters representing the propagation effect of radiation through the observed object. McMehan [1] succeeded in developing an inversion method with an iterative approach for cross-hole reconstruction tomography, which was further developed by Sanny [2]. Travel time tomography generally uses a raytracing approach which is the arrival time or the first break based on Fermat's principle.…”

Section: Introductionmentioning

confidence: 99%

“…In this study, we focused to get the inversion result using Eikonal's solver and Fresnel volume approach. We used Modified Simultaneous Iterative Reconstruction Technique which was developed by Sanny [2].…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic Tomography of Core Plug Using Fresnel Volume Approach

Aryan,

Sanny,

Septama

et al. 2023

IOP Conf. Ser.: Earth Environ. Sci.

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Tomography was a non-destructive method for investigating the internal structure of an object, usually used to find internal anomalies caused by differences in the physical parameters. The fresnel volume tomography method was an alternative method for reconstructing the image of an object using travel times, whereas this method did not use a ray path in its calculations. In calculating the fresnel zone, the finite difference method which was the solution to the equation of wave propagation was used. The frequency of the waves was also considered, here we used ultrasonic waves with a frequency of 1 Mhz for the inverse modelling process. The reconstruction algorithm we used was Modified Simultaneous Iterative Reconstruction Technique for Fresnel volume. The application of the inversion of synthetic data resulted in an estimation of a velocity model that has good imaging quality and similarity with the synthetic model.

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