Madagascar: open-source software project for multidimensional data analysis and reproducible computational experiments

Fomel, Sergey; Sava, Paul; Vlad, Ioan; Liu, Yang; Bashkardin, Vladimir

doi:10.5334/jors.ag

Cited by 240 publications

(37 citation statements)

References 9 publications

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“…The reproducible numeric examples in this paper use the Madagascar opensource software package (Fomel et al, 2013) freely available from http://www.ahay.org. The authors thank Tariq Alkhalifah for helpful discussions and valuable suggestions.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Scalar imaging condition for elastic reverse time migration

2015

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Polarity changes in converted-wave images constructed by elastic reverse time migration cause destructive interference after stacking over the experiments of a seismic survey. This polarity reversal is due to PS and SP reflectivities reversing sign at certain incidence angles, e.g., at normal incidence in isotropic media. Many of the available polarity correction methods are complex and require costly transformations, e.g., to the angle domain. We derive a simple imaging condition for converted waves to correct the image polarity and reveal the conversion strength from one wave mode to another. Our imaging condition exploits pure P-and S-modes obtained by Helmholtz decomposition. Instead of correlating Cartesian components of the vector S-mode with the P-mode, we exploit all three components of the S wavefield at once to produce a unique image. We generate PS and SP images using geometric relationships among the propagation directions for the P-and S-wavefields, the reflector orientation, and the S-mode polarization direction. Compared with alternative methods for correcting the polarity reversal of PS and SP images, our imaging condition is simple and robust and does not significantly increase the cost of reverse time migration. Several numerical examples were used to test the effectiveness of our new imaging condition using simple and complex models.

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Section: Acknowledgmentsmentioning

confidence: 99%

Scalar imaging condition for elastic reverse time migration

2015

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“…Thus using a 2D acoustic RTM code is kinematically correct. The algorithm we worked with is based on a 2D finite difference modeling code included in the Madagascar software package [19]. The modeling program we worked with uses a regular grid and is accurate fourth-order in space and second-order in time.…”

Section: Reverse-time Migrationmentioning

confidence: 99%

Geometry Determination of a Foundation Slab Using the Ultrasonic Echo Technique and Geophysical Migration Methods

2016

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The ultrasonic echo technique is a frequently used method in non destructive testing for geometry determination of concrete building elements. Important tasks are thickness measurements as well as the localization and characterization of built-in components and inhomogeneities. Currently mainly the synthetic aperture focusing family of techniques (SAFT) is used for imaging. These algorithms have difficulties in imaging steeply dipping interfaces and complicated structures such as steps and lower boundaries of voids. As an alternative two geophysical migration methods, pre-stack Kirchhoff depth migration and pre-stack Reversetime migration (RTM) were tested in this paper at a reinforced concrete foundation slab. The slab consists of various reinforcement contents, different thicknesses and two pile heads. In a first step, both methods were evaluated with synthetic 2D data. In the second step, ultrasonic measurement data recorded with shear wave transducers on a line profile on the foundation slab were processed. The use of an automatic scanner simplified the measurements. A comparison of the geophysical migration results with those of SAFT shows, in particular for RTM, a significant improvement in the imaging of the geometry of the foundation slab. Vertical borders were reconstructed and the location and structure of the lower B Maria Grohmann boundary of the foundation slab were reproduced better. Limitations still exist in imaging the piles below the slab.

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“…The reproducible numeric examples in this paper use the Madagascar open-source software package (Fomel et al, 2013) freely available from http://www.ahay.org. The reproducible numeric examples in this paper use the Madagascar open-source software package (Fomel et al, 2013) freely available from http://www.ahay.org.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Vertical Seismic Profile Complete Session

2016

SEG Technical Program Expanded Abstracts 2016

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Madagascar: open-source software project for multidimensional data analysis and reproducible computational experiments

Cited by 240 publications

References 9 publications

Scalar imaging condition for elastic reverse time migration

Scalar imaging condition for elastic reverse time migration

Geometry Determination of a Foundation Slab Using the Ultrasonic Echo Technique and Geophysical Migration Methods

Vertical Seismic Profile Complete Session

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