Broadband laboratory measurements of dispersion in thermally cracked and fluid-saturated quartzite and a synthetic analogue
Bibliographic record
Abstract
Abstract In the field, the seismic waves used for active-source imaging typically contain frequencies from 10 to about 100 Hz, with corresponding wavelengths of tens of meters. This contrasts greatly with the ultrasonic (∼ 1-MHz) wave-speed measurements carried out in the laboratory, with millimeter wavelengths. The purpose of the laboratory measurements is, of course, to provide insight into seismic wave speeds in situ. However, with the presence of a pore fluid, velocity measurements are sensitive to the frequency at which velocity data are collected. A study focuses on such fluid-flow-related dispersion by performing a broadband measurement in the laboratory from millihertz (mHz) to megahertz (MHz) frequencies on a natural quartzite and on a synthetic sintered glass-bead sample. Thermal cracks that have small aspect ratios of about 10−4 to 10−3 were introduced in both samples, which are of low porosities (1% to 2%) even after thermal cracking. A seismic-frequency forced-oscillation method is combined with a high-frequency ultrasonic technique, providing access to a wide frequency range. Under water-saturated conditions, the observed seismic wave speeds display substantial variations between seismic and ultrasonic frequencies in the cracked quartzite. A systematic increase in shear modulus, attributed to the suppression of fluid flow, has been monitored on the cracked glass-bead specimen with both argon and water saturation at ultrasonic frequency.
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 | 0.001 | 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) | 0.000 | 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".