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Neighbourhood inversion of teleseismic<i>Ps</i>conversions for anisotropy and layer dip

2003· article· en· W2145729420 on OpenAlex
A. W. Frederiksen, H. Folsom, G. Zandt

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.
aboutThe title or abstract carries a Canadian signal from the geographic lexicon.

Bibliographic record

VenueGeophysical Journal International · 2003
Typearticle
Languageen
FieldEarth and Planetary Sciences
Topicearthquake and tectonic studies
Canadian institutionsUniversity of WinnipegUniversity of ManitobaGeological Survey of Canada
Fundersnot available
KeywordsGeologyInversion (geology)AzimuthReceiver functionAnisotropySeismologyCrustSeismogramPrestackLithosphereGeophysicsGeometryTectonicsOpticsPhysics

Abstract

fetched live from OpenAlex

The inversion of teleseismic receiver functions for lithospheric structure is difficult due to the non-linearity of the problem, which is greatly increased in the presence of dipping interfaces and layer anisotropy. Given an efficient ray-theoretical tool for forward-modelling teleseismic seismograms, we perform a directed Monte Carlo search technique using the neighbourhood algorithm of Sambridge, enabling us to search 20–30 parameters in a reasonable amount of computer time. Tests on synthetic data reveal inherent velocity–depth trade-offs in typical data sets, due to the limited moveout present in teleseismic Ps; the azimuth of the anisotropic symmetry axis and the strike of a dipping interface prove to be well-resolved given adequate backazimuthal coverage. We apply this technique to two single-station data sets. The first, from permanent station PGC, Vancouver Island, British Columbia, displays dipping low-velocity sediment layers in the mid-crust. The second, from a station at the northern end of the Tibetan plateau operating in 1991 and 1992, requires a sequence of thick crustal anisotropic layers to explain the observed pattern of receiver-function arrivals.

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.

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 categoriesInsufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.180
Threshold uncertainty score1.000

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)0.0010.000

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 head0.017
GPT teacher head0.233
Teacher spread0.216 · 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