Bibliographic record
Abstract
The geographical distribution of the sense of the first motion of P waves (and to a very limited extent, S waves) has been studied by seismologists to provide information on the focal mechanism of earthquakes. In this thesis we investigate the inverse problem; knowing the type and form of displacement at the focus at the focal instant, we study the azimuthal distribution of the sense of first P and S motion, using model seismic technique. The source of elastic energy is a thermally induced tensile fracture in a glass plate. Two types of fractures have been studied: Initial (Bilaterally propagating) Fractures and Extended (Unilaterally propagating) Fractures. The azimuthal distribution of the P and S wave amplitudes is indicated. The experiments reported in this thesis constitute a partial test of a recent theory by Knopoff and Gilbert (1960) on first motions from seismic sources. The type of fracture studied corresponds to Case 3 of Knopoff and Gilbert. Our results show significant discrepancies with the theory. The sense of the measured first S motion is opposite to that predicted by the theory, for both Initial and Extended Fractures. The ratios Pө /P₉₀ and Sө/Pө differ in magnitude from the theory in many azimuths. It is suggested that the discrepancies are possibly due to the neglect in the theory of non-linear elastic effects near the tip of the fracture.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.013 | 0.001 |
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".