Analysis of strong and weak ground motions recorded at two sites during Loma Prieta earthquake by wavelet transform
Bibliographic record
Abstract
This paper explores the applicability of wavelet transform for the analysis of strong and weak ground motions recorded on rock at Yerba Buena Island and on dredged sandfill at nearby Treasure Island about 2 km away during the 1989 Loma Prieta earthquake in California. An interpretation of the results from this analysis is presented and discussed. The major important feature of this data set is that liquefaction occurred at the Treasure Island site during the strong shaking. The Daubechies 20-coefficient wavelet transform is utilized in this study. Results of the application of the wavelet transform can be summarized as follows: most of the energy of the earthquake at the Treasure Island site is in the frequency range of 0.581.77 Hz and arrives in the time interval between 11 and 15 s. For the Yerba Buena Island site, most of the energy lies within the frequency range of 1.153.53 Hz and arrives between 8 and 13 s. The analysis indicates that there are some large peaks at the highest resolution in the wavelet transforms at the Treasure Island site, which can be attributed to a progressive change in the stiffness characteristics of the soil.Key words: wavelet transform, Fourier transform, frequency content, wavelet scale, site response.
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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 | 0.001 | 0.001 |
| 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 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".