Felt Intensity versus Instrumental Ground Motion: A Difference between California and Eastern North America?
Bibliographic record
Abstract
We examine the question of whether a single ground-motion intensity correlation equation (GMICE) is applicable to both eastern North America (ENA; intraplate) and California (interplate). We initially address this issue with the datasets from previous studies and separate them into central United States (CUS), California, and Canada datasets. We then add data from the 2008 M 5.2 Mt. Carmel, Illinois, and the 2005 M 4.7 Riviere du Loup earthquakes to the CUS and Canada datasets, respectively. For each dataset, the median of ground-motion values at each modified Mercalli intensity (MMI) level and their 95% confidence limits are calculated for peak ground velocity (PGV), peak ground acceleration (PGA), and spectral acceleration (SA) at 0.3, 1.0, and 2.0 s. The California median value is relatively higher than the CUS and Canada for PGV and SA at 1.0 and 2.0 s. Based on the median values and the associated uncertainty, we combine all datasets for PGA and 0.3-s SA in order to determine a GMICE. The CUS and Canada datasets are combined separately from California for PGV, 1.0-s SA, and 2.0-s SA. ENA earthquakes have a different spectral shape than those in California, particularly at intermediate periods (∼1.0 s) where ENA spectral amplitudes are reduced, which may explain the difference we see at longer periods. Finally, a log-linear-fit of MMI to the median values of ground motion is used to determine GMICE.
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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 | 0.000 | 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 | 0.001 |
| 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".