Bumping the Crust

At www.scientificamerican.com/article.cfm?id=japan-earthquake-moves-seafloor we learn that the Fukushima earthquake moved the sea floor as much as 50m laterally and 16m vertically. In addition, the crust as a whole did not move forwards by 50m but varied between the coastline and the nearby trench (thought to be a subduction zone) which means that closer to the coast it was just a movement of a few feet, and out at sea rising to 20 and 30m and even further out to 50m movement. This appears to signify a stretching of the crust in concert with the bump itself – which is an interesting observation. Was the English Channel and North Sea basin also stretched?