Precursory seismicity changes associated with the 1999 August 17 Izmit (Turkey) earthquake
Bibliographic record
Abstract
We investigated precursory seismicity in and around the epicentral zone of the Mw= 7.4 1999 August 17 Izmit (Turkey) earthquake, by applying a statistical method—the RTL (Region–Time–Length) algorithm—to earthquake catalogues derived from that for the period 1981–1999 of Kandilli Observatory and Earthquake Research Institute (KOERI). The derived catalogues are complete for events MD≥ 3 in most of western Turkey. After declustering aftershocks, we investigated the seismicity patterns preceding the Izmit event at local (Izmit tectonic zone) and national (Turkey) scales. The RTL parameter indicates that a period of seismic quiescence started at the end of 1995 and reached a minimum in December 1996. An activation phase lasting about three months followed. The main shock in Izmit and vicinity did not occur when the seismicity returned to its background level, but occurred with a delay of nearly 2.5 yr. We present a new parameter to quantify the spatial distribution of seismic quiescence. The results from both catalogues indicate that a significant quiescence anomaly appeared in 1996 around the epicenter of the Izmit earthquake. The primary characteristics of the seismicity patterns prior to the Izmit earthquake are similar to those obtained for large events in Russia and Japan. The variations of seismicity patterns revealed by the RTL algorithm may offer better understanding of the physical nature of seismo-tectonics and provide useful information for seismic hazard estimation. The varying characteristics of the Izmit and other events may reflect the difference between seismo-tectonics in Turkey and in other regions such as Russia and Japan.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 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".