Deep-Sea Borehole Fluid Pressure and Temperature Observations at Subduction Zones and their Geodynamic Implications
Bibliographic record
Abstract
Seafloor and subseafloor temperature and pressure monitoring has been carried out with CORK (“Circulation Obviation Retrofit Kit”) sealed deep-ocean borehole observatories since their original design and deployments in 1991 in hydrologically and tectonically active settings. In this paper, we review results from twenty installations at six subduction zones that have provided novel insights into the thermal and hydrologic state, time-dependent deformation, and elastic properties of the subseafloor. Monitoring depths reached the levels of the megathrust faults beneath the outer subduction prisms at Nankai, Costa Rica, and Barbados, but only at the last were substantially elevated average pressures observed (excess fluid-pressure ratios of ~ 0.3 and 0.5). Otherwise, all records are characterized by fluid pressures only slightly super-hydrostatic. Transient pressure anomalies are observed to be common within both the subduction prisms and the incoming subducting plates. These reflect deformation (volumetric strain changes) caused by distant seismogenic fault slip at the time of large earthquakes, and by more local slow slip that is seen to propagate to the outermost reaches of the prisms from greater depths at rates of several kilometers per day. No such activity is seen at the Cascadia prism site, however, suggesting that its subduction fault is more completely locked. Where CORK observatories are co-located with or near seismometers and other seafloor monitoring instruments and are connected to cable systems for power, real-time high-rate data acquisition and precise timing, the observations allow relationships among seismic ground motion, seafloor pressure, and formation pressure to be defined. These, in turn, constrain formation elastic properties, and confirm the efficiency and fidelity with which strain is converted to formation pressure.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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 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".