Abstract: Acoustic velocity and elastic moduli profiles and corresponding fracture density and orientation patterns in artificially shocked granite: preliminary results
Bibliographic record
Abstract
Impact events can be simulated at a small scale in the laboratory and the subsequent crater can be examined to learn more about cratering processes. This work investigates subsurface fracture patterns beneath craters and the relationships between fracture density and orientation and acoustic velocity anomalies. Previous research in the laboratory and larger scale seismic surveys across impact craters on the Earth’s surface show that shock damage reduces the compressional wave velocities in the rock. Shear wave velocities measured as a part of this study complement the compressional wave velocities reported in the literature. The collection of a more complete data set allows calculation of Vp/Vs ratios and the derived elastic moduli profiles across an artificial crater produced by the Lindhurst Laboratory of Experimental Geophysics at the California Institute of Technology, Pasadena, California. Preliminary results show that shear wave velocities are more sensitive to the presence of fractures and resolve more widespread damage than compressional wave velocities, thus shear wave velocities or Vp/Vs ratios can be used to map a more complete picture of impact induced damage. Shear wave velocity measurements in three directions show anisotropy which has been attributed to the presence of different fracture populations and orientations. Future work will compare crack orientation in more detail with acoustic velocity and elastic moduli profiles; thin section observations will allow better characterization of fracture populations. Results from this study have implications for understanding cratering effects on solid surfaces throughout the solar system.
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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 | 0.000 |
| 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".