Question

On December 2006, 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 hr. what was the speed of the wave?

• A. 400 km/hr
• B. 1600 km/hr
• C. 800 km/hr
• D. Data insufficient

Answer 1

The correct option is C 800 km/hr

crest to crest distance is wavelength λ = 800 km

Time period: Time taken for wave to travel a distance of one wavelength = 1 hr

Wave velocity = $\frac{Distance}{Time}=\frac{1wavelength\left(\lambda \right)}{Timeperiod\left(T\right)}$

$\frac{800km}{1}=800km/hr$