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Record W2101273387 · doi:10.1190/geo2011-0367.1

Large-scale inversion of ZTEM data

2012· article· en· W2101273387 on OpenAlexaff
Elliot Holtham, Douglas W. Oldenburg

Bibliographic record

VenueGeophysics · 2012
Typearticle
Languageen
FieldEarth and Planetary Sciences
TopicGeophysical and Geoelectrical Methods
Canadian institutionsUniversity of British ColumbiaUniversity of British Columbia Hospital
Fundersnot available
KeywordsInversion (geology)DiscretizationAlgorithmBlock (permutation group theory)Computer scienceDomain decomposition methodsScale (ratio)Set (abstract data type)Polygon meshGeologyComputational scienceGeometryMathematicsComputer graphics (images)Finite element methodPhysicsMathematical analysisSeismology

Abstract

fetched live from OpenAlex

ABSTRACT A Z-Axis Tipper Electromagnetic Technique (ZTEM) survey is an airborne natural source electromagnetic survey that relates the vertical magnetic field to the horizontal magnetic fields measured at a reference station on the ground. For large airborne surveys, the high number of cells required to discretize the entire area at a reasonable resolution can make the computational cost of inverting the data set all at once prohibitively expensive. We present an iterative methodology that can be used to invert large natural source surveys by using a combination of coarse and fine meshes as well as a domain decomposition that allows the full model area to be split into smaller subproblems, which can be run in parallel. For this procedure, the entire data set is first inverted on a coarse mesh. The recovered coarse model and computed fields are used as starting models and source terms in the subsequent tiled inversions. After each round of tiled inversions, the tiles are merged together to form an update model, which is then forward modeled to determine if the model achieves the target misfit. Following this procedure, we first invert the data computed from a large synthetic model of the Noranda mining camp. The inverted models from this example are consistent among our different tiling choices. The recovered models show excellent large-scale agreement with the true model and they also recover several of the mineralized zones that were not apparent from the initial coarse inversion. Finally, we invert a 30×30 km block of the 2010 ZTEM survey collected over the porphyry Pebble Deposit in Alaska. The inverted ZTEM results are consistent with the results obtained using other electromagnetic methods.

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 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: Observational · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.799
Threshold uncertainty score0.953

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)0.0000.001

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 head0.034
GPT teacher head0.256
Teacher spread0.222 · 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 teacher head, 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

Citations12
Published2012
Admission routes1
Has abstractyes

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