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).
A shallow water wave is one that travels through water having a depth less than 1/20 of its wavelength. Knowing that the average Pacific Ocean depth is roughly three miles, oceanographers can determine the speed of the tsunami, and calculate the time it will take to travel between any two points. This information led to the development of travel-time charts that make it possible to predict the arrival time of a tsunami wherever it is generated.