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).
There are various factors that determine how far inland a tsunami  can go. Here is a list of factors involved: The terrain of the land  and the height of the tsunami wave. Iâ¦f the land is mountainous the  tsunami would probably not go very far; however, if it is lowland,  it may wash inland for several kilometers.