| Title | Long-period response spectra of large scenario earthquakes in British Columbia
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| Author | Molnar, S; Ventura, C E; Finn, W D L; Cassidy, J F ; Olsen, K B; Dosso, S E |
| Source | Proceedings of the 11th Canadian Conference on Earthquake Engineering; 2015 p. 1-8 |
| Image |  |
| Year | 2015 |
| Alt Series | Earth Sciences Sector, Contribution Series 20150045 |
| Publisher | Canadian Association of Earthquake Engineers |
| Meeting | 11th Canadian Conference on Earthquake Engineering; Victoria; CA; July 21-24, 2015 |
| Document | book |
| Lang. | English |
| Media | paper |
| File format | pdf |
| Province | British Columbia |
| NTS | 104; 103; 94; 93; 82 |
| Lat/Long WENS | -139.1500 -114.8667 59.9167 49.0833 |
| Subjects | geophysics; engineering geology; earthquakes; earthquake mechanisms; earthquake studies; plate motions; strong motion seismology; seismic risk; earthquake risk |
| Illustrations | location maps; block diagrams; tables; spectra |
| Program | Public Safety Geoscience Western Canada Geohazards Project |
| Released | 2015 01 01 |
| Abstract | Numerical simulation of large scenario earthquakes is at the forefront of seismic hazard analysis, with the potential to replace use of ground-motion prediction equations (GMPEs) in future.
Three-dimensional finite-difference numerical simulation of earthquake wave propagation has been used to predict long-period (= 2 s) ground motions of potential large scenario earthquakes in British Columbia: a M9 Cascadia subduction zone mega-thrust
earthquake, M6.8 deep earthquakes in the subducting oceanic plate, and M6.8 shallow earthquakes in the over-riding continental plate (Molnar et al. 2014b). New proposed ground motions for the 2015 National Building Code of Canada, up to spectral
periods of 10 s, provide the opportunity to compare simulated long-period ground motions and predicted ground motions based on proposed 2015 NBCC GMPEs for the first time. This paper compares long-period response spectra estimated from 2015 NBCC
GMPEs and 3D earthquake rupture simulations for potential large earthquakes in British Columbia. |
| Summary | (Plain Language Summary, not published)
Building code provisions currently use near-surface geological conditions as a proxy for estimating variations in earthquake ground shaking. However, in
areas of large sedimentary basins (such as Greater Vancouver) deep ¿basin structure¿ can play a very significant role in altering ground shaking and the resulting damage patterns from earthquakes. For example, in the 1995 M 6.9 Kobe Japan earthquake,
damage was concentrated along the edge of a basin. In this study we use detailed basin models, realistic shallow earthquake scenarios, and advanced computer modelling to examine the variation in earthquake shaking across southwest BC associated with
shallow earthquakes. Our study shows that sedimentary basin significantly alter the ground shaking (much more than near-surface geology currently used in building codes) with ¿deep basin¿ amplification factors of up to 8 times and much longer
duration shaking (moderate shaking increasing from 3 s to 25 s duration). Studies such as this one will contribute to improving future versions of codes and standards for buildings and infrastructure. |
| GEOSCAN ID | 296408 |
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