A tsunami warning is in effect for much of the Alaskan coast after a 7.8M quake occurred at 2020-07-22 06:12:44 (UTC) at location 55.030°N 158.522°W and at 28.0 km depth.
This is a relatively shallow depth, and an earthquake of this size is capable of producing a significant Tsunami. Especially, considering, there is vertical plate movement in the mechanism at the Alaskan plate. (Meaning that a large vertical wave may be produced).
Of course, plate mechanisms can vary from each location, along the plate boundary, however there is a good likelihood that a Tsunami has been generated – hence the warning. Not all Tsunami warnings “go to plan”, however, it is not worth taking that risk.
It is possible that some waves could reach the west coast of North America, however will of course have weakened quite a bit.