Bibliographic record
Abstract
Depressions 10–50 cm in diameter and O(10) cm deep were observed in rotary acoustic imagery of the seafloor during SandyDuck97. The rotary sonar record spans a 77 day period and 13 storm events. The depressions occurred during both the wave growth and the wave decay phases of each storm and over a relatively narrow range of wave energies (urms = 0.32 cm/s ± 0.05 cm/s standard deviation) and grain roughness Shields parameters(=0.7 ± 0.2). The observations are mainly from the outer surf zone in ≈3 m mean water depth at two stations separated by 40 m cross‐shore distance. Depressions were 6.5 times more frequent at the inner station (N = 485) than at the outer (N = 75). Areal densities were small: O(0.1) m−2. Depressions were also observed in the inner surf zone at a third station, for which the data record is less complete. The probability distribution of the locations of depression first occurrences is nonrandom (i.e., non‐Poisson) due to 50% reoccurrence in roughly the same positions from storm to storm. The geometry and temporal development of the depressions are similar to scour pits formed by cylindrical piles and other objects. On the basis of these similarities, and the clustering of first occurrence locations, we conclude that the likely origin of the depressions is scour about compact semimobile obstacles on or embedded within the sandy seafloor. Possible candidate obstacles include pebbles, large shells or large shell fragments, and the chimney structures left by burrowing organisms. Importantly, 13 of the pits evolved into meter‐scale lunate megaripples, indicating that these features can act as megaripple precursors.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 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".