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Adjoint centroid-moment tensor inversions

2011· article· fr· W1885207547 on OpenAlexaff
Young‐Hee Kim, Qinya Liu, Jeroen Tromp

Bibliographic record

VenueGeophysical Journal International · 2011
Typearticle
Languagefr
FieldEarth and Planetary Sciences
TopicHigh-pressure geophysics and materials
Canadian institutionsUniversity of Toronto
Fundersnot available
KeywordsSeismogramHessian matrixCentroidTensor (intrinsic definition)MathematicsConjugate gradient methodApplied mathematicsMathematical analysisInverse problemMoment (physics)GeologyGeometryAlgorithmPhysicsSeismologyClassical mechanics

Abstract

fetched live from OpenAlex

We determine centroid-moment tensor (CMT) solutions by minimizing waveform differences between observed and simulated seismograms based on an adjoint method. Synthetic seismograms and Fréchet derivatives are calculated based on a spectral-element method. The non-linear adjoint CMT inversion algorithm requires three simulations for each iteration: one ‘forward’ simulation to obtain synthetics for the current source parameters, one ‘adjoint’ simulation which involves injecting time-reversed differences between observed and simulated seismograms as simultaneous virtual sources at each of the receivers, and an extra forward simulation to compute the step length in the conjugate-gradient direction. Whereas the vertical component of the adjoint wavefield reflects the radiation pattern near the centroid location, the components of the adjoint strain tensor capture the elements of the moment tensor. We use the method to determine adjoint CMT solutions for two representative southern California earthquakes using recent 3-D crustal model CVM-6.2. The adjoint CMT solutions are in good agreement with classical Hessian-based CMT solutions involving 3-D Green's functions. In general, adjoint CMT inversions require fewer numerical simulations than traditional Hessian-based inversions. This faster convergence holds promise for multiple moment-tensor and kinematic rupture inversions in 3-D earth models.

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)0.001
metaresearch head score (Gemma)0.003
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: Simulation or modeling
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.005
Threshold uncertainty score0.012

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.003
Meta-epidemiology (narrow)0.0010.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0010.000
Scholarly communication0.0010.001
Open science0.0010.001
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0040.001

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 head0.043
GPT teacher head0.222
Teacher spread0.179 · 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 designSimulation or modeling
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

Citations85
Published2011
Admission routes1
Has abstractyes

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