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Record W2130315788 · doi:10.1190/1.1468604

Atmospheric sources for audio-magnetotelluric (AMT) sounding

2002· article· en· W2130315788 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

VenueGeophysics · 2002
Typearticle
Languageen
FieldEarth and Planetary Sciences
TopicSeismic Waves and Analysis
Canadian institutionsGeological Survey of Canada
Fundersnot available
KeywordsDepth soundingAmplitudeMagnetotelluricsGeologyDaytimeLightning detectionIonosphereAttenuationGeophysicsSIGNAL (programming language)Environmental scienceRemote sensingAcousticsMeteorologyPhysicsAtmospheric sciencesComputer scienceThunderstormOptics

Abstract

fetched live from OpenAlex

Abstract The energy sources for natural-source magnetotelluric (MT) frequencies > 1 Hz are electromagnetic (EM) waves caused by distant lightning storms and which propagate within the Earth–ionosphere waveguide. The properties of this waveguide display diurnal, seasonal, and 11-year solar-cycle fluctuations, and these temporal fluctuations cause significant signal amplitude attenuation variations—especially at frequencies in the 1- to 5-kHz so-called audiomagnetotelluric (AMT) dead band. In the northern hemisphere these variations increase in amplitude during the nighttime and the summer months, and they correspondingly decrease during the daytime and the winter months. Thus, one problem associated with applying the AMT method for shallow (<3 km) exploration can be the lack of signal in certain frequency bands during the desired acquisition in terval. In this paper we analyze the time variations of high-frequency EM fields to assess the limitations of the efficient applicability of the AMT method. We demonstrate that magnetic field sensors need to become two orders of magnitude more sensitive than they are currently to acquire an adequate signal at all times. We present a proposal for improving AMT acquisition involving continuous profiling of the telluric field only during the day-time and AMT acquisition at a few base stations through the night.

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 categoriesInsufficient payload (model declined to judge)
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Other design · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.832
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)0.0030.001

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 head0.016
GPT teacher head0.180
Teacher spread0.164 · 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