#### Answer

$v = 220~m/s$
$v = 800~km/h$
Since the wave speed was very fast, we can see that the waves carried a large amount of energy, which would be very destructive when the waves crashed onto the land.

#### Work Step by Step

Each wave crest traveled 800 km in 1.0 hour. We can find the speed of the wave in m/s.
$v = \frac{distance}{time}$
$v = \frac{8\times 10^5~m}{3600~s}$
$v = 220~m/s$
Each wave crest traveled 800 km in 1.0 hour. We can find the speed of the wave in km/h.
$v = \frac{distance}{time}$
$v = \frac{800~km}{1.0~h}$
$v = 800~km/h$
Calculating the speed helps us to understand why the waves caused such devastation. Since the wave speed was very fast, we can see that the waves carried a large amount of energy, which would be very destructive when the waves crashed onto the land.