Ambient Vibration Modal Analysis of Natural Rock Towers and Fins
Bibliographic record
Abstract
Abstract The dynamic properties of freestanding rock towers are important inputs for seismic stability and vibration hazard assessments, however data describing the natural frequencies, mode shapes, and damping ratios of these landforms remain rare. We measured the ambient vibration of 14 sandstone and conglomerate rock towers and fins in Utah, United States, using broadband seismometers and nodal geophones. Fundamental frequencies vary between 0.8 and 15 Hz—inversely with tower height—and generally exhibit subhorizontal modal vectors oriented parallel to the minimum tower width. Modal damping ratios are low across all features, between 0.6% and 2.2%. We reproduced measured modal attributes in 3D numerical eigenfrequency models for 10 of the 14 landforms, showing that the fundamental mode of these features is full-height bending akin to a cantilever. Fin-like landforms commonly have a torsional second mode whereas tower-like features have a second full-height bending mode subperpendicular to the fundamental. In line with beam theory predictions, our data confirm that fundamental frequencies scale with the ratio of a tower’s width to its squared height. Compiled data from 18 other sites support our results, and taken together, provide guidance for estimating the modal properties of rock towers required for vibration risk assessment and paleoseismic shaking intensity analysis in different settings.
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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 | 0.000 |
| 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) | 0.001 | 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".