Earthquake Hazard Maps Of The City Of Ottawa, Canada, Using Near-Surface Geophysical And Geological Methods
Bibliographic record
Abstract
The city of Ottawa, Ontario, Canada, is in an area of elevated earthquake shaking hazard and is considered to be the Canadian city third-most at risk to damage (after Vancouver and Montreal). Maps showing regional variation of Vs30, fundamental site period, and an example map of the spectral accelerations at Sa=0.2s have been completed for the city at a reconnaissance scale. These have been developed from combined geological information from ~21,000 boreholes (water wells and geotechnical borings) within the city limits as well as ~700 surface and borehole shear wave seismic measurement sites. Borehole and surface shear wave measurement techniques developed for the operational area included: surface reversed refraction and reflection sites, MASW, downhole shear wave and horizontalto- vertical spectral analyses of ambient noise. The surficial geology was subdivided into three basic units based on their geotechnical properties: (i) soft, fine-grained, post-glacial sediments, (ii) glacial till and coarse-grained, till-derived sediments, and (iii) firm Paleozoic and PreCambrian bedrock. A series of shear wave velocity-depth functions were assigned to each borehole based on interpolation from proximal geophysical sites. The resulting three-dimensional shear wave velocity database was then used to determine parameters such as Vs30 and fundamental site period. The Vs30 map of the city is subdivided in terms of the U.S. National Earthquake Hazard Reduction Program (NEHRP) zones which have been adopted by the 2005 National Building Code of Canada. Since the City of Ottawa has a large areal extent and is close to the West Quebec Seismic zone, the base accelerations for the 2% in 50 year<br>earthquake event vary extensively within the city boundaries. Hence an example map of the spectral accelerations at Sa=0.2s has been developed to demonstrate regional variations and the effects of NEHRP zones.
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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 | 0.000 |
| 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 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".