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Three-dimensional inversion of ZTEM data

2010· article· en· W2169096904 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

VenueGeophysical Journal International · 2010
Typearticle
Languageen
FieldEarth and Planetary Sciences
TopicGeophysical and Geoelectrical Methods
Canadian institutionsUniversity of British Columbia
Fundersnot available
KeywordsInversion (geology)MagnetotelluricsGeologySynthetic dataData setRemote sensingTransfer functionAlgorithmGround truthGeodesyGeophysicsComputer scienceMathematicsSeismologyPhysicsElectrical resistivity and conductivityStatisticsEngineering

Abstract

fetched live from OpenAlex

Z-Axis Tipper Electromagnetic Technique (ZTEM) data are airborne electromagnetic data which record the vertical magnetic field that results from natural sources. The data are transfer functions that relate the local vertical field to orthogonal horizontal fields measured at a reference station on the ground. The transfer functions depend on frequency and provide information about the 3-D conductivity structure of the Earth. The practical frequency range is 30–720 Hz and hence it is possible to see structures at depths of a kilometre or more if the earth is of moderate conductivity. This depth of penetration is significantly greater than that obtained with controlled source EM techniques and, when coupled with rapid spatial acquisition with an airborne system, means that ZTEM data can be used to map large-scale structures that are difficult to survey with ground based surveys. We present some fundamentals about understanding the signatures obtained with ZTEM transfer functions and then develop a Gauss–Newton algorithm to invert ZTEM data. The algorithm is applied to synthetic examples and to a field data set from the Bingham Canyon region in Utah. The field data set requires a workflow procedure to estimate appropriate noise levels in individual frequency components. These noise levels can then be used to invert multiple frequencies simultaneously. ZTEM data are insensitive to a 1-D conductivity structures and hence the background can be difficult to estimate. We provide two methods to determine appropriate background models. Interestingly, topography, which is usually a hinderance in field data interpretation, provides a first-order signal in the ZTEM data and helps with this calibration.

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: Other design · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.945
Threshold uncertainty score0.997

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 science0.0010.000
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0040.000

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 head0.030
GPT teacher head0.273
Teacher spread0.243 · 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