Seismic investigations of a vent field associated with gas hydrates, offshore Vancouver Island
Bibliographic record
Abstract
A three‐dimensional seismic reflection survey was carried out over a gas hydrate field offshore Vancouver Island in the area of Ocean Drilling Program Leg 146, Site 889/890. The area of investigation is located on the accretionary prism of the Cascadia margin in water depths of 1200–1500 m. Several seismic blank zones were observed in the seismic data over a frequency range from 30 Hz to 3.5 kHz, where the degree of blanking increases with seismic frequency. Time slices and selected horizon slices were used to define the spatial distribution of the blank zones. The zones range from 80 m to several hundred meters in width. One blank zone, almost circular with a diameter of ∼400 m, has a distinct seafloor expression. It shows the characteristics of a mud/carbonate mound and is probably associated with free gas expulsion. Hydrate was found at four sites with a piston corer within this blank zone at depths of 3–8 m below the seafloor. We present a tectonic model that explains the blank zones to be a result of differential uplift along thrust faults. The blank zones represent conduits for fluids and gas migrating upward. Blanking of the seismic energy is believed to be mainly the result of increased hydrate formation in lenses within the faults. The blanking effect is enhanced locally because of scattering at carbonates formed at the seafloor.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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 teacher head, 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".