An earthquake on the ocean floor in the Gulf of Alaska produces a tsunami (sometimes incorrectly called a "tidal wave") that reaches Hilo, Hawaii, 4,440km away, in a time interval of 6hr 30 min. Tsunamis have enormous wavelengths (100 to 200 km). From the information given, find the average ocean depth between Alaska and Hawaii. (This method was used in 1856 to estimate the average depth of the Pacific Ocean long before soundings were made to give a direct determination.) Propagation speed of the wave,