Modeling Site Amplification in Eastern Canada on a Regional Scale

Research Article| June 08, 2016 Modeling Site Amplification in Eastern Canada on a Regional Scale Sebastian Braganza; Sebastian Braganza aDepartment of Earth Sciences, Biological & Geological Sciences Building, Western University, 1151 Richmond Street, London, Ontario, Canada N6A 5B7sbragan@uwo.ca Search for other works by this author on: GSW Google Scholar Gail M. Atkinson; Gail M. Atkinson aDepartment of Earth Sciences, Biological & Geological Sciences Building, Western University, 1151 Richmond Street, London, Ontario, Canada N6A 5B7sbragan@uwo.ca Search for other works by this author on: GSW Google Scholar Hadi Ghofrani; Hadi Ghofrani aDepartment of Earth Sciences, Biological & Geological Sciences Building, Western University, 1151 Richmond Street, London, Ontario, Canada N6A 5B7sbragan@uwo.ca Search for other works by this author on: GSW Google Scholar Behzad Hassani; Behzad Hassani aDepartment of Earth Sciences, Biological & Geological Sciences Building, Western University, 1151 Richmond Street, London, Ontario, Canada N6A 5B7sbragan@uwo.ca Search for other works by this author on: GSW Google Scholar Luc Chouinard; Luc Chouinard bDepartment of Civil Engineering and Applied Mechanics, MacDonald Engineering Building, McGill University, 817 Sherbrooke Street West, Montreal, Québec, Canada H3A 0C3 Search for other works by this author on: GSW Google Scholar Philippe Rosset; Philippe Rosset bDepartment of Civil Engineering and Applied Mechanics, MacDonald Engineering Building, McGill University, 817 Sherbrooke Street West, Montreal, Québec, Canada H3A 0C3 Search for other works by this author on: GSW Google Scholar Dariush Motazedian; Dariush Motazedian cDepartment of Earth Sciences, Herzberg Laboratories, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6 Search for other works by this author on: GSW Google Scholar Jim Hunter Jim Hunter dGeological Survey of Canada, 601 Booth Street, Ottawa, Ontario, Canada K1A 0E8 Search for other works by this author on: GSW Google Scholar Author and Article Information Sebastian Braganza aDepartment of Earth Sciences, Biological & Geological Sciences Building, Western University, 1151 Richmond Street, London, Ontario, Canada N6A 5B7sbragan@uwo.ca Gail M. Atkinson aDepartment of Earth Sciences, Biological & Geological Sciences Building, Western University, 1151 Richmond Street, London, Ontario, Canada N6A 5B7sbragan@uwo.ca Hadi Ghofrani aDepartment of Earth Sciences, Biological & Geological Sciences Building, Western University, 1151 Richmond Street, London, Ontario, Canada N6A 5B7sbragan@uwo.ca Behzad Hassani aDepartment of Earth Sciences, Biological & Geological Sciences Building, Western University, 1151 Richmond Street, London, Ontario, Canada N6A 5B7sbragan@uwo.ca Luc Chouinard bDepartment of Civil Engineering and Applied Mechanics, MacDonald Engineering Building, McGill University, 817 Sherbrooke Street West, Montreal, Québec, Canada H3A 0C3 Philippe Rosset bDepartment of Civil Engineering and Applied Mechanics, MacDonald Engineering Building, McGill University, 817 Sherbrooke Street West, Montreal, Québec, Canada H3A 0C3 Dariush Motazedian cDepartment of Earth Sciences, Herzberg Laboratories, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6 Jim Hunter dGeological Survey of Canada, 601 Booth Street, Ottawa, Ontario, Canada K1A 0E8 Publisher: Seismological Society of America First Online: 14 Jul 2017 Online Issn: 1938-2057 Print Issn: 0895-0695 © 2016 by the Seismological Society of America Seismological Research Letters (2016) 87 (4): 1008–1021. https://doi.org/10.1785/0220160009 Article history First Online: 14 Jul 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Sebastian Braganza, Gail M. Atkinson, Hadi Ghofrani, Behzad Hassani, Luc Chouinard, Philippe Rosset, Dariush Motazedian, Jim Hunter; Modeling Site Amplification in Eastern Canada on a Regional Scale. Seismological Research Letters 2016;; 87 (4): 1008–1021. doi: https://doi.org/10.1785/0220160009 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search ABSTRACT A critical component in the interpretation of earthquake ground motions is the role that site effects play. In eastern Canada, the sediment layers which overlie glaciated bedrock produce strong and highly variable site responses. We use horizontal‐to‐vertical (H/V) response spectral ratios as the indicator variable by which to characterize the salient characteristics of site response. We show that site response can be modeled using two key descriptive variables that are readily obtainable: (1) peak frequency (fpeak), as determined from H/V or sediment depth; and (2) overall sediment type (or stiffness). We use these variables to create a preliminary model of site amplification that can be used in the development of ground‐motion prediction equations (GMPEs) and in regional‐scale ShakeMap‐type applications.The key to the site characterization is the relationship between fpeak and sediment thickness (depth‐to‐bedrock), which we derive using H/V data from earthquakes in the region, combined with compiled geophysical logs and a digital sediment thickness map from the Ontario Geological Survey (OGS). The OGS map also provides information on surficial sediment type, which is correlated with peak amplitudes (Apeak) of response. H/V spectral shapes may be associated with four main site categories, which in decreasing order of stiffness are: bedrock, till, sand/clay, and organic sediment/fill. The peak amplitudes of response are generally shown to increase as stiffness decreases, at least for the weak motions that are the focus of this study. We model site response by defining a generic site amplification curve, which is dependent only on fpeak and site category. These site amplification curves can be applied in the development of regional GMPEs, and in the construction of near‐real‐time ShakeMaps. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.