Minutes following a powerful 9.0 magnitude earthquake hitting off the coast of Vancouver Island on a summer day, a significant number of individuals in British Columbia are either deceased or injured amidst the chaos of the aftermath. Subsequently, a tsunami, aftershocks, and general confusion add to the devastation. Distraught survivors flood hospitals in search of missing loved ones, while the region’s infrastructure, including roads and railways, suffer damage from the quake and subsequent flooding. Shortages of essential supplies such as food and medical resources exacerbate the crisis.
A detailed risk analysis by the B.C. government paints a grim picture of a potential “megathrust” earthquake scenario, forecasting over 3,400 fatalities and more than 10,000 injuries on the day of the main tremor. The report mentions that additional casualties would result from secondary hazards triggered by the earthquake, including tsunamis, aftershocks, and fires. The estimated costs amount to $128 billion, with 18,000 buildings destroyed and 10,000 more severely damaged. The economic repercussions are severe, with a halving of economic growth, significant GDP losses, and job cuts anticipated over the next decade, surpassing the cumulative impact of all historical disasters in B.C. over the last two centuries.
The analysis highlights that the most severe destruction could occur on Vancouver Island and a coastal stretch of approximately 20 kilometers in the lower mainland encompassing Vancouver, extending from the U.S. border to the Sunshine Coast. The report is part of the broader B.C. disaster and climate risk assessment from October 2025, which also outlines various extreme event scenarios, including severe flooding in the Fraser Valley, high-tide flooding on the southwest coast post winter storms, urban interface fires, and prolonged droughts.
Edwin Nissen, an earth and ocean sciences professor at the University of Victoria, emphasized that the report’s estimations of fatalities and property damage are based on sophisticated simulations. Nissen highlighted the importance of considering factors such as the construction materials and location of buildings in assessing their vulnerability to seismic activities. He mentioned that wooden structures generally fare better during earthquakes compared to brick buildings and emphasized the significance of the underlying geological formations in mitigating damages.
Nissen cautioned that there is a considerable amount of uncertainty surrounding the figures in the report due to variables like the timing of the earthquake. He stressed the necessity of regular updates to emergency preparedness reports to keep pace with evolving scientific and engineering advancements.
The report references the last similar earthquake in the region occurring in 1700, with knowledge obtained from First Nations’ oral traditions and modern scientific studies of the Cascadia fault line. The likelihood of a comparable extreme event in the next 30 years is estimated between two to ten percent, with the 2004 Indian Ocean earthquake serving as a comparable reference in terms of tectonic characteristics and tsunami generation.
Despite the last major earthquake occurring centuries ago, Nissen pointed out that seismic events of this magnitude do not occur predictably. He underscored the importance of continual preparedness, as earthquakes could strike at any moment. Nissen also highlighted the scientific community’s limited understanding of the Cascadia subduction zone due to the scarcity of moderate seismic activities in the area, emphasizing the need for enhanced monitoring and preparedness measures.
