Answer to Question #288765 in Physics for NICKO

Question

On December 26, 2004, a great earthquake occurred off the coast of Sumatra and triggered immense waves (tsunami) that killed some 200,000 people. Satellites observing these waves from space measured 800 km from one wave crest to the next and a period between waves of 1.0 hour. What was the speed of these waves in m/s and in km/h? Does your answer help you understand why the waves caused such devastation?

Answer 1

The speed is wavelength divided by time (or period):

$$v=800/1=800\text{ km/h},\\ u=800·10^3/(1·3600)=222\text{ m/s}.$$

The tsunami waves traveled at the speed of airplane.