| Title | Bayesian trans-dimensional inversion of surface-wave dispersion for earthquake site response estimation in Northern British Columbia, Canada |
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| Author | Gosselin, J M; Cassidy, J F ; Dosso, S E; Brillon, C |
| Source | Seismological Research Letters vol. 87, no. 2B, 2016 p. 449 |
| Links | Download entire publication / téléchargement de la publication au complet (21.7 MB)
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| Year | 2016 |
| Alt Series | Earth Sciences Sector, Contribution Series 20160056 |
| Publisher | Seismological Society of America |
| Meeting | Seismological Association of America Annual Meeting; Reno, NV; US; April 20-22, 2016 |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Subjects | tectonics; Science and Technology; s waves; earthquake studies; earthquakes; modelling; array seismology; Bayesian inversion |
| Program | Public Safety Geoscience Western Canada Geohazards Project |
| Released | 2016 01 01 |
| Abstract | Knowledge of the shear-wave velocity (Vs) profile over the upper 10s of metres of the soil column is important for characterizing the expected ground response to earthquake shaking at a specific site.
Non-invasive and passive methods based on recording ambient seismic noise are increasingly popular for estimating Vs structure with minimal cost and site disruption. This study applies an advanced Bayesian inversion methodology to estimate Vs
structure from surface-wave dispersion measurements processed from passive seismic array recordings using frequency-wavenumber analysis. A fully non-linear trans-dimensional (trans-D) Bayesian inversion based on parallel tempering is used to estimate
Vs models and associated model uncertainties. In trans-D inversion, the model parameterization (e.g., number of layers of the Vs profile) is included as an unknown which is sampled probabilistically, accounting for the uncertainty of the model
parameterization in the uncertainty of the model parameter estimates. Shear-wave velocity profiles and uncertainties are obtained from the velocity-depth marginal distribution of the trans-D posterior probability density. These probabilistic results
for the Vs profile allow for probabilistic estimates of site response factors such as peak ground velocity/acceleration and amplification/resonance spectra, which ultimately quantify the confidence in the site characterization. This methodology is
applied to passive seismic array recordings collected at five sites in Kitimat, British Columbia, Canada. Inversion results from several sites are compared to active-source (vibroseis) reflection data collected nearby. |
| Summary | (Plain Language Summary, not published)
This study examines earthquake site response at a number of locations in Kitimat, British Columbia, where soft soils are expected to cause significant
variations in earthquake shaking. We use a small seismic array recording ¿background noise¿ to determine shear wave velocity profiles ¿ a key parameter used in the National Building Code for seismic hazard calculations. We develop and apply an
improved ¿inversion methodology¿ that provides not only shear wave velocity profiles, but also a greatly improved estimate of uncertainty in the derived profiles. This allows us to quantify the confidence in the earthquake site characterization. We
also compare our inversion results to active-source (vibroseis) reflection data collected nearby. |
| GEOSCAN ID | 298751 |
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