Thermal and structural models of the Sumatra subduction zone: Implications for the megathrust seismogenic zone
Bibliographic record
Abstract
The 2004 Sumatra‐Andaman and 2005 Nias events provide unique geodetic and seismic data constraining the updip and downdip rupture extents of great thrust earthquakes. These limits are important for tsunami generation and earthquake shaking, respectively. There is a consistent downdip limit of rupture along strike in these great earthquakes at a depth of ∼30 km, and there is an updip limit near the trench that are interpreted to define the seismogenic limits. Temperature and downdip changes in formation compositions are controls proposed for these limits. To examine the thermal control, we developed 2‐D finite element models of the Sumatra subduction zone with smoothly varying subduction dip, variable thermal properties of the rock units, frictional heating along the rupture planes, and appropriate thermal state of the incoming plate. The common updip thermal limit for seismic behavior of 100–150°C occurs close to or at the trench in agreement with the great earthquake rupture limit. Off central Sumatra the common downdip thermal limit range of 350–450°C occurs at 30–60 km depth. The 350°C location is in agreement with the earthquake limits, but 450°C is deeper. North of Sumatra, 350°C occurs ∼14 km deeper than the earthquake rupture limit. The proposed composition control for the downdip limit, the intersection of the subduction thrust with the fore‐arc mantle, is at a depth of ∼30 km, 140–200 km from the trench, in good agreement with the earthquake limits. These results support the conclusion that the Sumatra updip seismogenic limit is thermally controlled but the downdip limit is governed by the intersection of the downgoing plate with the fore‐arc Moho.
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 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 | 0.001 | 0.001 |
| 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".