A profile of earthquake risk for the District of North Vancouver, British Columbia

Abstract

The societal costs of natural hazards are large and steadily increasing in Canada due to increased urban development, an aging infrastructure, and limited capacities to anticipate and plan for unexpected disasters. Lessons learned from recent disasters underscore the need for a comprehensive risk-based approach to land use planning and emergency management at all levels of government-one that utilizes available knowledge about the risk environment to inform actions that have a potential to minimize future disaster losses and increase the resilience of communities to the dynamic and uncertain forces of change. We cannot predict or prevent earthquakes from happening. However, we do have the knowledge and capabilities to change the outcome of earthquake disasters through a combination of risk assessment and disaster resilience planning. Risk assessment is the process through which knowledge about a community and its exposure to natural hazards is used to anticipate the likely impacts and consequences of an unexpected event at some point in the future. Disaster resilience planning is focused on actions that can be taken in advance to balance policy trade offs for growth and development (opportunities) with risk reduction investments that have a potential to minimize future losses (liabilities) while increasing capabilities of a community to withstand, respond to and recover from unexpected disaster events (resilience). This study provides a detailed assessment of earthquake risk for the District of North Vancouver - an urban municipality of approximately 83,000 people situated along the North Shore Mountains in southwestern British Columbia. It describes the probable impacts of a significant earthquake with greater clarity and detail than ever before, and develops both a methodology and target criteria to guide future risk reduction and disaster resilience planning activities through the lens of building performance, public safety, lifeline resilience and socioeconomic security. We examine cause-effect relationships and seismic risks for a plausible earthquake scenario in the Strait of Georgia (M7.3), and undertake a more general assessment of who and what are vulnerable to known earthquake hazards in the region using probabilistic ground motion models that are consistent with those used to establish seismic safety guidelines in the National Building Code of Canada (NBCC, 2010). Study outputs offer a capacity to explore thresholds of risk tolerance and opportunities for mitigation through ongoing emergency planning and land use decision-making activities in the community. Methodologies and insights gained through this study are transferrable to other communities who may face similar challenges of managing growth and development in areas exposed to earthquake hazards. Key findings and recommendations of the study contribute to broader efforts led by the Canadian Safety and Security Program to support disaster resilience planning at a community level in Canada.

Characterizing Uncertainty in City-Wide Disaster Recovery through Geospatial Multi-Lifeline Restoration Modeling of Earthquake Impact in the District of North Vancouver

“…Many of the parameters used in the GMOR model for this study are derived from Hazus information produced in a previous study conducted by The Geological Survey of Canada on the vulnerability of infrastructure in the selected case study area (Journeay et al 2015). Hazus data utilized include the probability of occurrence for varying levels of damage as well as repair and recovery parameters for the different infrastructure systems.…”

“…The district is situated in an area that is subject to seismic hazard and is at risk of a large earthquake in the future. An earlier study (Journeay et al 2015), conducted by the district in partnership with Natural Resources Canada (NRCan) and a number of other research partners, examined the effects of an earthquake on local infrastructure systems. This study evaluated the likelihood and effects of known hazards in the region before completing a comprehensive assessment of a reference-case magnitude 7.3 shallow earthquake centered in the nearby Strait of Georgia.…”

“…This study evaluated the likelihood and effects of known hazards in the region before completing a comprehensive assessment of a reference-case magnitude 7.3 shallow earthquake centered in the nearby Strait of Georgia. Hazard information for this earthquake was then processed with Hazus to determine the direct effects and probabilities of failure of the various infrastructure systems of interest (DNV 2015;Journeay et al 2015).…”

“…In this model, water distribution and wastewater collection network failures and probabilities of failure for power and road networks are correlated to those established (but unpublished) for use in the previous district study of a magnitude 7.3 earthquake (Journeay et al 2015).…”

Evaluating the Use and Communication of Seismic Hazard Maps: A Case Study of Metro Vancouver, British Columbia, Canada

“…Hence, most Canadian seismic microzonation maps depict soil hazard using V S30 or its associated NBCC site class [3], [16], [20]- [23]. The V S30 -based site classification system is the generally accepted method of defining the hazard potential of earthquake shaking/amplification [3], [4], [24]. Amplification of ground motion is affected by the fundamental site period (T S ) or the inverse, the resonance frequency, of a site [25].…”