If I may ...
Well ..... I included no calculations for seafloor irregularities such as the Atlantic's ocean plate divergent boundary line, or the rise and depth of the sea floor accounting for the volume of water that would be carrying the transfer of wave energy to our shores. It was just a simply equation; D÷T=S. Time divided by distance equals speed. So 3375 miles ÷ 8 hours = 421.875 miles per hour.
But yes, it could be an inverted Marianas Trench wall of water traversing, based on the size of the land mass that could slide into the western Atlantic, seeing as in total with the land mass and the depth in which it would fall beneath the water line, 4000 meters, or 13,123.360 Feet, at La Palma's base to the bottom of the Atlantic, if that's what you meant?
Just being wordy to be wordy btw.