3.11 Volcanoes in British Columbia

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Garibaldi Volcanic Belt

Southwestern BC volcanic chain formed by subduction of the Juan de Fuca Plate beneath the North American Plate (Cascade Volcanic Arc extension).

Magma Generation in the Garibaldi Belt

Driven by flux melting above the subducting Juan de Fuca / Explorer Plate, producing intermediate-to-felsic magmas and explosive stratovolcanoes.

Key Volcanoes of the Garibaldi Belt

Mount Garibaldi, Mount Meager, Mount Price, Mount Cayley, and Black Tusk.

Anahim Volcanic Belt

Volcanic chain in central BC formed by intraplate mantle plume (hotspot) volcanism as the North American Plate moves westward over a hot spot.

Nazko Cone

The youngest, easternmost volcanic center in the Anahim Volcanic Belt, located near Quesnel, BC, directly above the mantle plume.

Rainbow Range

A large, deeply eroded shield volcano in central BC formed ~8 million years ago along the Anahim Volcanic Track.

Northern Cordilleran Volcanic Province / Stikine Belt

Volcanic region in northwestern BC driven by crustal extension and rifting, producing primarily basaltic magmas.

Tseax Cone Eruption (~1775 AD)

Canada's deadliest volcanic event; a cinder cone eruption and basaltic lava flow in northwestern BC where asphyxiating gases (mostly CO2) killed ~2,000 Nisga'a people.

Mount Meager Eruption (~2,400 BP)

Canada's most recent major explosive eruption (~2,350 to 2,400 years ago) that spread ash as far east as Alberta; remains structurally unstable today.

Tuya

A steep-sided, flat-topped volcano formed when an eruption occurs beneath glacial ice, leaving a flat lava cap once the ice melts (e.g., The Table near Garibaldi Lake).

Mount Edziza Volcanic Field

A large volcanic complex in northwestern BC featuring cinder cones, mafic lava flows, and a central composite volcano exhibiting magma differentiation.

Transboundary Volcanic Risk to BC

Mount Baker, an active composite volcano in Washington State visible from Vancouver, posing ashfall, lahar, and flooding risks to southwestern BC.

Volcanic Hazard Context in Manitoba

Manitoba has no active volcanoes today; its volcanic rocks in the Canadian Shield (e.g., metamorphosed basalts) are ancient Precambrian rocks over 2 billion years old.

Primary Engineering Relevance of Volcanism in Coastal BC

Infrastructure design must account for localized volcanic hazards, seismic shaking, landslides, lahars, and volcanic ashfall.