# name
Seismic site period studies for nonlinear soil in the city of Ottawa, Canada

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This publication focuses on creating maps for earthquake response studies in Ottawa and Gatineau, where there are areas with soft, silty-clayey sediments due to post-glacial deposits, which make up 60% of these urban regions. To prepare the maps, the researchers used data fromthousands of boreholes and various geophysical measurements.The maps serve different purposes:1. T0,ESL map: It's based on a common method described in Canada's building code and helps estimate earthquake response at typical levels of ground shaking.2. T0,HVSR map: This map uses a different method to estimate earthquake response, particularly for weaker ground shaking, revealing variations influenced by soil properties.3. T0,100 map: This map is designed for moderate ground shaking levels, showing how the soil behaves as shaking intensifies.4. T0,400 map: It focuses on higher levels of ground shaking, reflecting how soft soils behave during strong earthquakes.By comparing these maps, the researchers found that in areas with soft soil, the ground's response to severe shaking differs significantly from what you might expect from typical modeling methods. This information is crucial for earthquake preparedness and urban planning, ensuring that buildings andinfrastructure can withstand the potential impact of strong earthquakes.

# metadata.dc.description[].value
Cette publication se concentre sur la création de cartes pour les études de réponse aux tremblements de terre à Ottawa et à Gatineau, où se trouvent des zones avec des sédiments mous et limono-argileux dus à des dépôts postglaciaires, qui constituent 60 % de ces régionsurbaines. Pour préparer les cartes, les chercheurs ont utilisé les données de milliers de forages et diverses mesures géophysiques.Les cartes répondent à différents objectifs :1. Carte T0,ESL : Elle est basée sur une méthode courante décrite dans le code du bâtiment du Canada et permet d'estimer la réponse aux tremblements de terre à des niveaux typiques de secousses du sol.2. Carte T0,HVSR : Cette carte utilise une méthode différente pour estimer la réponse aux tremblements de terre, en particulier pour les secousses du sol plus faibles, révélant des variations influencées par les propriétés du sol.3. Carte T0,100 : Cette carte est conçue pour des niveaux de secousses modérés du sol, montrant comment le sol se comporte à mesure que les secousses s'intensifient.4. Carte T0,400 : elle se concentre sur des niveaux plus élevés de secousses du sol, reflétant le comportement des sols mous lors de forts tremblements de terre.En comparant ces cartes, les chercheurs ont découvert que dans les zones au sol mou, la réponse du sol à de fortes secousses diffère considérablement de ce que l'on pourrait attendre des méthodes de modélisation classiques. Ces informations sont cruciales pour la préparation aux tremblements deterre et la planification urbaine, garantissant que les bâtiments et les infrastructures peuvent résister à l'impact potentiel de forts tremblements de terre.

# metadata.dc.description.abstract[].value
Site period maps at various strain levels were developed for the combined cities of Ottawa and Gatineau in eastern Ontario and western Quebec. These maps were developed to support earthquake response studies in areas containing post-glacial, soft, silty-clayey sediments,which comprise 60% of the urban areas. Approximately 21,700 boreholes and over 1000 surface and downhole geophysical measurements were utilized to prepare the maps. The maps include the following: 1) A T0,ESL map is based on an equivalent single-layer modelling method (ESL) as described in theNational Building Code of Canada using the 4H/V approach. 2) A T0,HVSR map is based on the micro-tremor HVSR method, which systematically deviates from T0,ESL for weak motion. Such variances between the calculated T0,ESL and measured T0,HVSR may be associated with significant shear wavevelocity-depth gradients in the near-surface soft sediments. 3) A T0,100 map is based on finite element modelling at the 100 cm/s/s level of shaking (0.1 g) at the onset of the "gray zone" between the linear and nonlinear soil responses. 4) A T0,400 map is developed from a finite element model atthe 400 cm/s/s level of shaking (0.4 g being the "design" earthquake for the city of Ottawa) This model evaluates the effect of nonlinear soft soil behaviour. The differences between these maps were examined and compared. The results indicated that nonlinear soil response at high levels of shakingstrongly altered the resonance response toward much longer fundamental periods over large areas within the two cities.

# metadata.dc.title[].value
Seismic site period studies for nonlinear soil in the city of Ottawa, Canada