A mechanism for transient creep in crustal shear zones
Bibliographic record
Abstract
The brittle-to-ductile transition in faults and shear zones marks the change from frictional stick-slip behavior in the seismogenic zone to creep accommodated by plastic mechanisms at higher temperatures. Geodetic observations of slow slip events (SSEs) on plate-boundary shear zones indicate that transient periods of elevated aseismic slip rate occur beneath the seismogenic zone where dislocation creep is likely to be active. SSE duration on the San Andreas fault (California, USA) and major subduction zones decreases systematically with increasing depth and temperature. However, current flow laws for dislocation creep are unable to explain the occurrence of transients similar to SSEs. We develop a microphysical model of dislocation creep that shows how small perturbations in stress (of the order kPa) can lead to strain-rate transients orders of magnitude faster than the background during nominally steady-state flow. The model explains the first-order characteristics of SSEs, reconciling the geophysical observations of deep slow slip events with expectations from experimental rock mechanics. Given that these microphysical mechanisms are general to rock-forming silicate minerals, our results suggest that non-steady-state deformation is inherent to natural shear zones that deform by dislocation creep and that the transition from brittle to steady-state creep occurs over a broad depth range within which transients are predominant.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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 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".