The location of Microseismic events and the Propagation of Ray path and gridded traveltimes for depth migration using locally spherical wavefronts
Bibliographic record
Abstract
SummaryAn efficient algorithm is presented that estimates the apparent source of a microseismic event from the first arrival clock-times at four receiver locations in a 3D volume. Wavefronts are assumed to be locally spherical in a constant velocity medium. Applications for identifying the apparent source range from monitoring hazardous geological sites, estimating the distribution of well fraccing material, the monitoring of sequestered CO2, or global positioning from satellite data.The clock-time of the source may also be estimated, extending applications to Kirchhoff depth migrations in which traveltimes on a grid may be computed directly, or may be estimated from traveltimes computed along raypaths. The traveltimes at additional grid points can be computed from the apparent source. In heterogeneous media, wavefronts may have an arbitrary shape, but can be considered to be circular over a small region in the neighbourhood of the known points. The velocity in this region is assumed to be constant and may be extended, without error, to enclose the apparent source point.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".