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Record W2322858211 · doi:10.1071/aseg2001ab147

Generalised ray parameters for vertically inhomogeneous and anisotropic media

2001· article· en· W2322858211 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueASEG Extended Abstracts · 2001
Typearticle
Languageen
FieldEarth and Planetary Sciences
TopicSeismic Imaging and Inversion Techniques
Canadian institutionsMemorial University of Newfoundland
Fundersnot available
KeywordsAnisotropyIsotropyConserved quantityMathematical analysisPhysicsClassical mechanicsMathematicsOptics

Abstract

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In this presentation we derive a concise equation for a generalised ray parameter in inhomogeneous and anisotropic media. We illustrate the direct application of this conserved quantity by several examples, involving anisotropic parameters and linear velocity fields.The ray parameter, or raypath parameter, p, is a conserved quantity which plays an important role in both exploration and global seismology. The constancy of the ray parameter contributes to convenient methods of raytracing and imaging. The standard form of p in a homogeneous isotropic medium is the horizontal component of the slowless, expressed in terms of the angle measured from the normal to the interface between media, 0 , and the velocity, v. This ray parameter, p, is a conserved quantity, ie the first integral of the Euler-Lagrange equation.Increased interest in anisotropic characteristics of sedimentary rocks motivated this work, which provides an exact form of the ray parameter for vertically inhomogeneous and anisotropic media. We use the mathematical tools provided by calculus of variations, in particular the Euler-Lagrange equation with its first integrals, to arrive at this new form of the ray parameter. There always exists a conserved quantity, such as the ray parameter for arbitrarily complex velocity fields. For exploration seismology in sedimentary basins, a relevant form would account for vertical inhomogeneity and anisotropy. In such a case, the ray parameter resembles the standard form mentioned above with an additional term due to the anisotropy.The results allow for convenient modelling and raytracing. They permit certain investigations of the influence of anisotropy on ray trajectories and traveltimes, which play an important role in AVO analysis. Furthermore, presented results could be incorporated in data-processing applications.

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Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Other design · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.983
Threshold uncertainty score0.481

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.020
GPT teacher head0.226
Teacher spread0.206 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it