Variations in Reflection Signature and Slip Behavior of the Subduction Interface Offshore Alaska Peninsula From 152° to 161°W
Bibliographic record
Abstract
We present seismic reflection images of the plate interface down to a depth of ∼65 km across ∼130,000 km 2 offshore Alaska Peninsula. A thin reflection package (<2 km) characterizes the megathrust at depths <24–34 km, marking localized brittle deformation that likely hosts the largest seismic asperities. The reflection band thickness transitions from 2 to 5 km over depths of ∼24–41 km, suggesting a thickening zone of cumulative deformation and greater heterogeneity corresponding to conditionally stable megathrust behavior. At depths >35–41 km, the reflection package maintains a thickness of 5–6 km and marks the predominantly aseismically slipping megathrust areas. Historic and recent megathrust earthquakes in the southwest Kodiak Asperity and Semidi Segment generally occur within the thin and/or transitional reflection bands. The 2020 Simeonof and earlier M 7+ earthquakes in the Shumagin Gap are estimated to also rupture the shallowest section of megathrust characterized by the thick reflection band (∼35–41 km depth). Although the shallow part of the plate boundary (< ∼ 25 km deep) in the Semidi and Shumagin segments did not rupture in recent 2020 M 7.8 Simeonof and 2021 M 8.2 Chignik earthquakes, the seismic properties of the megathrust suggest it may be capable of earthquake slip in the future, as may have occurred in 1788.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".