A Reference Model of Crustal Thickness and <i>V</i><sub><i>p</i></sub>/<i>V</i><sub><i>s</i></sub> of Western Canada
Bibliographic record
Abstract
Abstract The Canadian Cordillera marks a transition region from the current plate boundary through the Phanerozoic Cordilleran orogen to the Precambrian cratons. Knowledge of the subsurface structure of western Canada has been greatly advanced by seismological investigations during the past two decades, pioneered by the Lithoprobe project and, more recently, by regional passive seismic arrays. In this study, we construct a new model (WCANM22) of crustal thickness and P‐ to S‐wave velocity ratio, or Vp/Vs, by compiling receiver function data from 473 stations and existing constraints from over 2,600‐km long active source experiments. Our model covers a broad swath (about 1/4) of the land area of North America (105°–140°W, 48°–72°N) and shows an overall flat Moho beneath the Cordillera with an average depth of ∼36 km and a standard deviation of 3 km across orogenic belts. This study provides a comprehensive catalog of Vp/Vs in western Canada and reveals a moderate correlation between Poisson's ratio and the age of crustal domains. The average Vp/Vs values are 1.72, 1.79, and 1.82 for the Phanerozoic Cordillera, Proterozoic Cratons, and Archean‐aged Medicine Hat Block, respectively, suggesting continued modifications to crustal composition through episodic tectonothermal events. This distinct trend in western Canada sheds new light on the debated role of secular changes in the composition of continental crust.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".