Probabilistic assessment of the vulnerability of buildings in seismic regions

风险评估和潜在自然灾害的缓解是加拿大大多数城市面临的关键问题。这些任务既需要准确预测危险，也需要仔细评估建筑物的脆弱性，尽管存在不确定性。用技术术语来说，灾害可以定量地描述为“特定强度的事件在特定地区发生的可能频率”，而脆弱性可以定义为“由物理、社会、经济和环境因素或过程决定的条件，这些因素或过程增加了社区对灾害影响的敏感性。”在自然灾害中，地震在加拿大某些地区是一种特别重要的危险。地震风险管理需要能够量化地震负面影响的风险分析。理想情况下，这一分析应该包括对影响进行概率量化的过程。为了更好地评估这些风险，该项目旨在开发一种损害模拟器，以评估在地震危险区域内发现的建筑物的脆弱性。开发这一模拟器需要一个相当准确的三维地质模型，对该领土进行充分的地震微区划，并对现有的基础设施和建筑物进行适当的脆弱性评估。研究项目的第一步是开发该地区的三维地质模型，为确定区域地震灾害提供基础。该模型应包括多个变量，包括地表沉积层的厚度和类型、基岩的深度和类型以及地下水位。以魁北克Charlevoix-Haute-Côte-Nord地区为例，我们将建立一个地表沉积物的三维模型，我们将能够根据该地区密度不同的现有数据确定与估算表层沉积物厚度相关的不确定性的影响。第二步是根据Charlevoix-Haute-Côte-Nord地区的现有数据和作为该项目一部分进行的一些新的实地测量，对区域地震灾害进行微区划。目前已有多种确定土体剪切波速的方法，但这些方法都受不确定因素的影响。该项目的这一部分将侧重于地震横波速度的不确定性在确定土壤类别和地震风险微区划方面的影响。基于建筑物脆弱性函数及其区域建筑物类型的不确定性，第三步将开发包含用于评估危险和脆弱性的应用方法的损坏模拟器。概率方法既可以解释与地震相关的不同程度的损害，也可以解释每种地震情景发生的概率。该损害模拟器将为参与管理地震风险的不同行为者提供决策支持工具。

Risk assessment and mitigation of potential natural hazards are critical issues facing most Canadian cities. These tasks require both an accurate prediction of the hazard and a careful evaluation of the vulnerability of buildings despite existing uncertainties. In technical terms, a hazard can be described quantitatively as "the likely frequency of occurrence of an event of a specific intensity in a given area," whereas vulnerability can be defined as "the conditions determined by physical, social, economic, and environmental factors or processes that increase the susceptibility of a community to the impact of hazards." Among natural disasters, earthquakes represent a particularly important hazard in certain regions of Canada. Seismic risk management requires a risk analysis that can quantify the negative impacts of an earthquake. Ideally, this analysis should include a process for the probabilistic quantification of impacts. To better assess these risks, this project aims to develop a damage simulator that will assess the vulnerability of buildings found within seismic hazard area. The development of this simulator requires a fairly exact 3-D geological model, an adequate seismic microzonation of the territory, and an appropriate vulnerability assessment of existing infrastructure and buildings. The first step of the research project involves developing a 3-D geological model of the territory that provides the basis for establishing regional seismic hazards. This model should include multiple variables including the thickness and the type of surficial deposit layers, the depth and type of bedrock, and groundwater levels. Using the Charlevoix-Haute-Côte-Nord region of Quebec as a case study, a 3-D model of surficial deposits will be produced from which we will be able to determine the effect of uncertainties associated with estimating the thickness of surficial deposits from available data that varies in density across the region. The second step is the microzonation of regional seismic hazards based on existing data for the Charlevoix-Haute-Côte-Nord region and some new field measurements carried out as part of this project. Multiple methods have been proposed for determining the soil shear wave velocity; all these methods are affected by uncertainties. This part of the project will focus on the effects of uncertainty vis-à-vis seismic shear wave velocity (Vs) in determining soil classes and seismic risk microzonations. Based on a building vulnerability function and its uncertainties for the regional building types, the third step will develop a damage simulator that incorporates the applied methodologies for assessing hazard and vulnerability. A probabilistic approach can account for both the variable levels of damage associated with earthquakes and the probability occurrence of each seismic scenario. This damage simulator will represent a decision-support tool for the different actors involved in managing seismic risks.