The largest island in a lake on an island in a lake on an island is a nameless 1.6-hectare (4-acre) island at 69Â°47â²35â³N 108Â°14â²28â³W / 69.793Â°N 108.241Â°W / 69.793; -108.241, 121 kilometres (75 mi) inland from the south coast of Victoria Island, Canada.
A tsunami can travel across the open ocean at about 500-miles per hour, the speed of a jet airliner. As the wave approaches land and as the ocean shallows, the wave slows down to about 30 miles-per-hour and grows significantly in height (amplitude).
Less than an hour after the earthquake, the first of many tsunami waves hit Japan's coastline. The tsunami waves reached run-up heights (how far the wave surges inland above sea level) of up to 128 feet (39 meters) at Miyako city and traveled inland as far as 6 miles (10 km) in Sendai.