Bibliographic record
Abstract
A key question in earthquake seismology is whether earthquake sources in different tectonic regions are functionally equivalent in terms of radiated ground motion. This article compares the apparent earthquake source radiation for six different regions: Japan, Mexico, Turkey, California, British Columbia (B.C.) (western Canada), and eastern North America (ENA). The source, path, and site effects were consistently separated to the extent possible to allow interregional comparisons of apparent source radiation. Large Fourier spectra databases were created for both horizontal and vertical components for earthquakes with magnitude between 2.5 and 7.5. Regional parameters characterizing source, path, and site properties, including crustal and near-surface site amplifications, were investigated to isolate apparent source spectra. Based on the vertical-component spectra at a reference distance of 1 km, a new magnitude scale m 1 was defined from the spectral level at 1 Hz. The magnitude scale m 1 is a natural complement to existing magnitude scales that measure the low-frequency and high-frequency spectral amplitudes (moment magnitude M and high-frequency m hf, respectively). In all regions, the apparent source spectra for small to moderate earthquakes ( M <6) show good agreement with the single-corner Brune (1970, 1971) point-source model ( ω 2 spectrum), suggesting a stress parameter of about 100 bars (10 MPa). A two-corner source model better matches the spectra for large-magnitude earthquakes ( M ≥6), especially at intermediate frequencies. For small to moderate events, the two source models are nearly equal. Apparent source spectra from small to moderate earthquakes (e.g., m 1 3.5-6.5) suggest a general similarity between the different tectonic regions studied. Although minor discrepancies appear in some cases, there are no noticeable regional characteristics. No evident depth effects were found on the apparent source spectra. Manuscript received 1 April 2001.
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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 | 0.002 | 0.002 |
| 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) | 0.002 | 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".