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Record W2078878647 · doi:10.1190/1.2792575

Azimuthal anisotropy: Is it really ubiquitous?

2007· article· en· W2078878647 on OpenAlexaboutno aff
Bryan DeVault

Bibliographic record

Venuenot available
Typearticle
Languageen
FieldEarth and Planetary Sciences
TopicSeismic Imaging and Inversion Techniques
Canadian institutionsnot available
Fundersnot available
KeywordsAnisotropyAzimuthGeologyDipoleShear wave splittingComputer scienceSeismologyGeophysicsPhysicsOptics

Abstract

fetched live from OpenAlex

Following the groundbreaking work of Crampin (1985), Alford (1986), Lynn and Thomsen (1990) and Lewis et al (1991), it quickly became conventional wisdom in the industry that substantial shear-wave azimuthal anisotropy is nearly ubiquitous in the subsurface. Crampin and Zatsepin (1995) made theoretical arguments that implied that most of the subsurface is azimuthally anisotropic. As industry's ability to measure and quantify azimuthal anisotropy at a variety of scales has grown, this assumption has remained largely unexamined. Looking at over a dozen datasets, including surface 9-C seismic, 9-C VSPs, and dipole sonic logs at a number of locations in the Western US and Alberta, I have seen little unambiguous evidence of azimuthal shear-wave anisotropy despite polarization analysis of each dataset.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.003
metaresearch head score (Gemma)0.016
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.006
Threshold uncertainty score0.017

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0030.016
Meta-epidemiology (narrow)0.0000.001
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0020.004
Science and technology studies0.0010.007
Scholarly communication0.0040.008
Open science0.0010.002
Research integrity0.0010.003
Insufficient payload (model declined to judge)0.0050.002

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 head0.252
Teacher spread0.232 · 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

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2007
Admission routes1
Has abstractyes

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