How can wasted energy be made useful?

Tsunamis are fast-moving waves often generated by underwater earthquakes. in the deep ocean their amplitude is barely noticeable, but upon reaching shore they can rise to an astonishing height of a six-story building. one tsunami generated off the aleutian islands in alaska, had a wavelength of 897km and traveled a distance of 3280km in 4.18h. (a) what was the speed (in m/s) of the wave? find the waves (b) frequency and (c) period.