From DisasterRelief.org:
The Cumbre Vieja volcano on the Canary Islands’ La Palma island may not erupt again for centuries, but when it does disaster could spread across oceans. Shaken loose by the eruption, a gigantic chunk of the mountain’s western flank could slide into the Atlantic – shoving massive tsunamis toward the coasts of Africa, Europe, South America, Newfoundland and possibly even the United States.
In the worst-case scenario (detailed in an article in the Sept. 1 issue of Geophysical Research Letters by geophysicists Steven Ward of the University of California at Santa Cruz and Simon Day of University College, London) half a trillion tons of volcanic rock would slip into the ocean.
Within five minutes, a wall of water would rise to 1,500-feet high and travel at high-speed 30 miles out to sea. The wave would weaken before it reached land, but it still could be 900 feet high when it would slam into nearby islands.
Over the next five to 45 minutes, a series of waves would ripple outward, their crests reaching 150 feet before barreling into the African coast, Spain and England.
Six hours after the eruption, waves reaching 30 feet would arrive in Newfoundland and 45- to 60-foot waves would bombard South America, swamping large parts of land. Nine hours after the eruption, crests reaching 30 to 70 feet would collide into the East Coast of the United States.