October 17, 1974 Tsunami: Kitimat Inlet, British Colombia, Canada

Reference #4153:

On October 17, 1974, in Kitimat Inlet, BC, a submarine slide generated a water wave of 2.8 m amplitude.[Murty, 1975; Murty and Brown, 19791].

Underwater slopes in fjords and inlets commonly attain a delicate equilibrium with the long-term ambient marine conditions associated with wave, current and tidal regimes, and the rate and character of sedimentation. This stability can be disrupted, leading to failure, by events or conditions that depart significantly from ambient conditions, Landslides, slumps and rock falls are often the secondary effects of earthquakes. [Rabinovich at al., 20031.

According to Johns et al., [ 19851, a slide event was believed to have taken place on October 17, 1974,

but its evidence was only circumstantial. A sea-surface wave reached approximately 2.4 m high, it was observed in the head of the inlet at 11:05 A.M. (LT), shortly after extreme low tide. The location of the seafloor sediment movement that might have caused this smaller wave was not determined. It is possible, however, that this event was related to the formation of a chute on the delta front/sidewall on the eastern side of the inlet. At this location, there was a chute that originated in a steeply sloping area at the intersection of the delta front, the inlet sidewall, and a distal part of a small fan delta near Kitimat Village.