The tectonics that caused the 1946 Vancouver Island earthquake are poorly known. No surface expression of the offset was noticed, most likely because the epicentre area is very remote and densely forested. A comprehensive examination and computer interpretation of seismic data from over 50 stations has shown that a possible explanation of the earthquake includes a strike-slip fault corresponding to the lengthy axis of Vancouver Island, known as the Beaufort Range Fault. A fault running across Vancouver Island, corresponding to the projection of the underwater Nootka Fault on the British Columbia Coast, is also a possibility but an unlikely one because the earthquake showed no evidence of offsets along a series of highways that follows much of the eastern coastline of Vancouver Island, called Island Highway, and other roads between Courtenay and Campbell River. The estimated depth of the earthquake places it within the continental crust, not at the margin with the Cascadia subduction zone, and certainly not inside the subduction zone itself. Specifically, the earthquake's epicentre was positioned somewhere in the Forbidden Plateau region, in central Vancouver Island.