Catalog of Offshore Seismicity in Cascadia: Insights Into the Regional Distribution of Microseismicity and its Relation to Subduction Processes
Bibliographic record
Abstract
Abstract We present a catalog of offshore seismicity generated from Cascadia Initiative (CI) ocean‐bottom seismometer data. Earthquakes were detected within the CI data using a short‐time‐average/long‐time‐average trigger and located using 1‐D velocity models developed from seismic reflection/refraction surveys. The catalog, which contains 271 earthquakes with magnitude 0.4–4.0 along the coasts of Vancouver Island, Washington, Oregon, and Northern California, spans all 4 years of the ocean bottom seismometer deployment and shows distinct along‐strike variations in seismicity consistent with structural observations from recent active source seismic reflection/refraction studies. Seismicity is sparse off Vancouver Island and Washington (49°N–46°N) but increases off northern and central Oregon, corresponding to a roughened, more deformed subducting slab. Widespread earthquakes are observed at near‐interface depths between 46°N and 45°N, though an increase in underthrust sediment thickness between 45°N and 43°N likely restricts seismicity to scattered asperities on the plate interface. South of 43°N, where both the overriding and subducting plates are severely deformed approaching the Mendocino triple junction, seismicity is abundant. We locate an additional 440 events in the Juan de Fuca plate seaward of the deformation front. The higher seismicity south of 46°N is consistent with more extensive intraplate deformation. Along with the complex stress field induced by the Mendocino triple junction, our observations imply that the smoothness and degree of hydration of the incoming plate, which are linked to the amount of underthrust sediment and extent of intraplate deformation, are major contributing factors to the distribution of microseismicity in the Cascadia subduction zone.
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".