A traveltime reciprocity discrepancy in the Podvin &amp; Lecomte<i>time3d</i>finite difference algorithm

Tryggvason, Ari; Bergman, Björn

doi:10.1111/j.1365-246x.2006.02925.x

Cited by 45 publications

(34 citation statements)

References 14 publications

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“…In the algorithm, the first arrival traveltimes are computed with the finite difference (FD) algorithm time3d (Podvin and Lecomte, 1991;Tryggvason and Bergman, 2006). Ray tracing is performed by a posteriori back propagation perpendicular to the wave fronts from the receivers to the transmitters (Hole, 1992 ε where small values provides a strong relative weight); and coupling of the two models by enforcing structural similarity via cross-gradients constraints (the weight given to this term is controlled by λ).…”

Section: The Inversion Methodsmentioning

confidence: 99%

Joint inversion of crosshole radar and seismic traveltimes acquired at the South Oyster Bacterial Transport Site

et al. 2008

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Abstract:The structural approach to joint inversion, entailing common boundaries or gradients, offers a flexible way to invert diverse types of surface-based and/or crosshole geophysical data. The cross-gradients function has been introduced as a means to construct models in which spatial changes in two models are parallel or anti-parallel. Inversion methods that use such structural constraints also provide estimates of non-linear and non-unique field-scale relationships between model parameters. Here, we invert jointly crosshole radar and seismic traveltimes for structurally similar models using an iterative non-linear traveltime tomography algorithm.Application of the inversion scheme to synthetic data demonstrates that it better resolves lithological boundaries than the individual inversions. Tests of the scheme on observed radar and seismic data acquired within a shallow aquifer illustrate that the resultant models have improved correlations with flowmeter data than with models based on individual inversions.The highest correlation with the flowmeter data is obtained when the joint inversion is combined with a stochastic regularization operator, where the vertical integral scale is estimated from the flowmeter data. Point-spread functions shows that the most significant resolution improvements of the joint inversion is in the horizontal direction.2

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Section: The Inversion Methodsmentioning

confidence: 99%

Joint inversion of crosshole radar and seismic traveltimes acquired at the South Oyster Bacterial Transport Site

et al. 2008

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“…This program uses finite (Tryggvason, Bergman, 2006). The raytracing is performed "backwards" perpendicular to the isochrons of the time field (Hole, 1992).…”

Section: Tomography Methodsmentioning

confidence: 99%

3D seismic travel time surveying a comparison of the time–term method and tomography (an example from an archaeological site)

Valenta

Dohnal

2007

Journal of Applied Geophysics

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“…This problem is made tractable by separation of the slowness and hypocenter perturbations (Pavlis and Booker, 1980;Spencer and Gubbins, 1980). This method calculates the theoretical travel times by finite difference solutions of the eikonal equation through a complex velocity structure (Podvin and Lecomte, 1991) (later modified by Tryggvason and Bergman, 2006). The great advantage of this technique is that it can solve transmitted and diffracted body waves in structures with large velocity contrasts.…”

Section: Tomographic Inversion Proceduresmentioning

confidence: 99%

3D tomographic imaging of the southern Apennines (Italy): A statistical approach to estimate the model uncertainty and resolution

et al. 2010

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A new dataset of first P-wave arrival times is used to derive the 3D tomographic model of the Campania-Lucania region in the southern Apennines (Italy). We address the issue related to the non-uniqueness of the tomographic inversion solution through massive numerical experimentation based on the global exploration of the model parameter space starting from a large variety of physically plausible initial models. The average of all the realizations is adopted as the best-fit solution and the uncertainty of the model parameters is studied using a statistical approach based on a Monte Carlo-type analysis. How the uncertainty in the initial model, earthquake locations, and data influences the inversion result is studied by considering separately the individual effects. Checkerboard tests are performed to estimate the resolving power of the dataset. Re-located seismicity in a reliable new 3D tomographic model allows us to correlate the earthquake distribution with the main seismogenic structures present in the area.

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A traveltime reciprocity discrepancy in the Podvin & Lecomtetime3dfinite difference algorithm

Cited by 45 publications

References 14 publications

Joint inversion of crosshole radar and seismic traveltimes acquired at the South Oyster Bacterial Transport Site

Joint inversion of crosshole radar and seismic traveltimes acquired at the South Oyster Bacterial Transport Site

3D seismic travel time surveying a comparison of the time–term method and tomography (an example from an archaeological site)

3D tomographic imaging of the southern Apennines (Italy): A statistical approach to estimate the model uncertainty and resolution

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