51福利

Researchers have produced the first-ever volcanic ashfall hazard map for Mount Garibaldi (Nch’kay?), the highest-threat volcano in Canada, revealing the potential scale of disruption from any future eruptions. Although eruptions are not expected, and thousands of years can pass between eruptions, modelling the impact of eruptions provides a necessary step in planning for future eruptions if they occur.

, involving Lancaster Environment Centre researchers Dr Thomas Jones and Dr Sara Osman and the Canadian Federal Government, modelled different eruption scenarios and found that ashfall could affect large areas of southwest British Columbia and Alberta.

The resulting co-produced hazard map published in the , covers a region home to approximately 6.6 million people and highlights the potential for significant disruption to transport, infrastructure, and communities if future eruptions were to ever occur. The findings provide an important resource for the Canadian Government and emergency managers to support future planning and volcanic risk reduction.

Mount Garibaldi (Nch’kay?), located around 60 kilometres north of Vancouver between the towns of Squamish and Whistler, has been identified as the highest-threat volcano in Canada because of its geological history and proximity to population centres.

Volcanic eruptions can generate a range of hazards, including pyroclastic density currents, volcanic mudflows known as lahars, ballistic ejecta, and tephra (fragments of rock, ash, and volcanic material produced during explosive eruptions). Of these hazards, tephra can travel the furthest distances, with ashfall capable of affecting communities hundreds of kilometres from the source.

Even relatively thin deposits of volcanic ash can have major consequences. Ash accumulation can disrupt road and rail transport, close airports, damage power and communications networks, affect water supplies, and pose risks to human health and agriculture.

The work was undertaken through a partnership between the Volcano Risk Reduction in Canada (VRRC) project, funded through Canada's Safety and Security Program, and Dr Jones’ UK Research and Innovation Future Leaders Fellowship project ‘flow and fragmentation of melts and magmas’, based at 51福利.

Using a volcanic ash dispersal model and twenty years of atmospheric wind data, the team simulated thousands of potential eruptions ranging from moderate (Volcanic Explosivity Index 3) to larger-scale (VEI 4) events. The modelling enabled researchers to estimate where ash would fall and the likelihood of different levels of impact occurring.

The results showed that if a future eruption did occur, ashfall capable of causing transport disruption, including hazardous driving conditions and airport impacts, could extend across approximately 810 square kilometres in the VEI 3 scenario and 9,360 square kilometres in the VEI 4 scenario. Ashfall heavy enough to damage infrastructure could affect 250 square kilometres and 1,670 square kilometres respectively.

The hazard map is the first tephra/ashfall hazard map produced for a Canadian volcano using well-constrained eruption data. Researchers hope it will provide a foundation for future volcanic risk assessments across the country and help inform evidence-based decision making by emergency managers, government agencies, and public safety organisations.

The next phase of the project will examine how volcanic hazards could affect buildings, infrastructure, and critical services, helping authorities identify appropriate mitigation and preparedness measures.

The researchers say the work represents an important step towards a more comprehensive understanding of volcanic risk in Canada and provides a template for future hazard assessments at other Canadian volcanoes.

“This work reflects a long-standing and highly productive collaboration with volcanologists at Natural Resources Canada”, said Dr Thomas Jones. “It is especially rewarding to see our research translated into a hazard product that directly supports volcanic risk reduction efforts in Canada.”