Multi-method site characterization to verify the hard rock (Site Class A) assumption at 25 seismograph stations across Eastern Canada
| العنوان: | Multi-method site characterization to verify the hard rock (Site Class A) assumption at 25 seismograph stations across Eastern Canada |
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| المؤلفون: | Sheri Molnar, Sameer Ladak, Samantha M. Palmer |
| المصدر: | Earthquake Spectra. 37:1487-1515 |
| بيانات النشر: | SAGE Publications, 2021. |
| سنة النشر: | 2021 |
| مصطلحات موضوعية: | In situ, Seismometer, Profiling (computer programming), 021110 strategic, defence & security studies, 0211 other engineering and technologies, 02 engineering and technology, 010502 geochemistry & geophysics, Geotechnical Engineering and Engineering Geology, 01 natural sciences, Characterization (materials science), Geophysics, Seismic hazard, Component (UML), Multi method, Geology, Seismology, 0105 earth and related environmental sciences |
| الوصف: | Site characterization is a crucial component in assessing seismic hazard, typically involving in situ shear-wave velocity ( VS) depth profiling, and measurement of site amplification including site period. Noninvasive methods are ideal for soil sites and become challenging in terms of field logistics and interpretation in more complex geologic settings including rock sites. Multiple noninvasive active- and passive-seismic techniques are applied at 25 seismograph stations across Eastern Canada. It is typically assumed that these stations are installed on hard rock. We investigate which site characterization methods are suitable at rock sites as well as confirm the hard rock assumption by providing VS profiles. Active-source compression-wave refraction and surface wave array techniques consistently provide velocity measurements at rock sites; passive-source array testing is less consistent but it is our most suitable method in constraining the rock VS. Bayesian inversion of Rayleigh wave dispersion curves provides quantitative uncertainty in the rock VS. We succeed in estimating rock VS at 16 stations, with constrained rock VS estimates at 7 stations that are consistent with previous estimates for Precambrian and Paleozoic rock types. The National Building Code of Canada uses solely the time-averaged shear-wave velocity of the upper 30 m ( VS30) to classify rock sites. We determine a mean VS30 of ∼ 1600 m/s for 16 Eastern Canada stations; the hard rock assumption is correct (>1500 m/s) but not as hard as often assumed (∼2000 m/s). Mean variability in VS30 is ∼400 m/s and can lead to softer rock classifications, in particular, for Paleozoic rock types with lower average rock VS near the hard/soft rock boundary. Microtremor and earthquake horizontal-to-vertical spectral ratios are obtained and provide site period classifications as an alternative to VS30. |
| تدمد: | 1944-8201 8755-2930 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::7ed8d3ea7ca0343ec0a4e8a4e2b9cef4 https://doi.org/10.1177/87552930211001076 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi...........7ed8d3ea7ca0343ec0a4e8a4e2b9cef4 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 19448201 87552930 |
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