Lithospheric structure and seismic anisotropy of the northern Appalachian region
Bibliographic record
Abstract
Over the course of more than 30 years, the seismic structure of the Appalachian Orogen of northern New England and Canada has been studied using several active- and passive-source methods. The resulting models shed light on present-day crust and upper-mantle wave speed structure, seismic anisotropy and their relationship to the complex geological history of the region. Notable contributions were made by the Lithoprobe East project in the 1980s/1990s, and by the EarthScope USArray in the 2010s. Crustal studies revealed significant heterogeneity across the northern Appalachians. Variations in upper- and mid-crustal seismic wave speeds correlate with metamorphic grade and composition across the Appalachian domains, and the interaction between the Laurentian margin and accreted terranes varies along strike. Crustal thicknesses typically range from ∼30 to 46 km. Lithospheric thicknesses vary from ∼70 to 120 km beneath Maine and the Canadian Maritimes, preserving orogenic structures including a potential signature of flat-slab subduction. Anisotropic orientations are oblique to orogenic trends in New England, but sub-parallel in the Canadian Appalachians, with spatial variations that suggest a significant contribution from lithospheric deformational fabric associated with Paleozoic orogenesis and later rifting processes.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".