Magma dynamics and collapse mechanisms during four historic caldera‐forming events
Bibliographic record
Abstract
Four historic caldera‐forming events were studied to understand the relationship of magma withdrawal processes and caldera subsidence mechanisms. Two calderas are silicic (Katmai in 1912 and Pinatubo in 1991), and two are basaltic (Fernandina in 1968 and Miyakejima in 2000). All events have sufficient geophysical, geologic, and petrologic data with which to examine and model magma withdrawal and caldera collapse. The data reveal that the magmas erupted at Katmai and Pinatubo were in a bubbly state in the reservoir immediately before and during caldera collapse. The bubbly magma allowed for its efficient extraction from the reservoir, causing significant underpressures to develop rapidly, particularly in the case of Katmai where the erupted rhyolite was voluminous and nearly aphyric and has very low viscosity. The rapidly developing underpressures at Katmai and Pinatubo caused sudden en masse caldera collapse halfway through the climactic eruptions, thereby liberating large amounts of seismic energy. At Fernandina and Miyakejima, by contrast, caldera collapse was initiated early and continued for an extended period of time from weeks to months, consisting of a series of discrete subsidence events manifested by large earthquakes at Fernandina and by very long period (VLP) signals at Miyakejima. Systematic changes in earthquake magnitudes and quiescent intervals at both volcanoes reveal changes in friction, as collapse took place during extended time intervals.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".