Deglacial record of palaeoearthquakes interpreted from mass transport deposits at three lakes near Rouyn‐Noranda, north‐western Quebec, Canada
Bibliographic record
Abstract
Abstract As part of an investigation of deglacial palaeoseismology within an intracratonic region of north‐eastern North America, the compilation of sub‐bottom acoustic profile surveys from study areas at Duparquet and Dufresnoy lakes, north‐western Quebec, Canada, produced thirteen and eight event horizon maps, respectively, depicting subaqueous mass transport deposits that are interbedded within Lake Ojibway glaciolacustrine varve deposits. Analysis of rhythmic couplets recovered in cores from both locations yielded varve ages with annual resolution for the event horizons relative to the regional Timiskaming varve series. These results are integrated with the published event horizon stratigraphy and varve chronology from nearby Lac Dasserat. The combined event horizon records for the three lakes overlap between varve years 1175 to 1625 (9395 to 8945 ± 200 cal year bp) and consist of 26 event horizons. Fifteen event horizons are inferred to be evidence of 11 palaeoearthquakes at qualitative levels of interpretative confidence varying from high to low. The palaeoearthquake interpretations and assessments of interpretative confidence are made from weightings of the event horizon signatures and, where possible, evidence supporting a stratigraphic footprint extending beyond a given study area. Occurring over a 450 varve year period when rapid crustal uplift was still underway, 11 interpreted palaeoearthquakes happened at an average rate of every ca 40 years. Relative to a published minimum threshold magnitude for generating a recognizable geomorphic signature, this average rate of occurrence exceeds the modern return period by two orders of magnitude. The palaeoearthquakes probably occurred within a period of elevated seismicity associated with rapid crustal unloading during deglaciation.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".