Beats the hell out of me.
But that won't stop me from guessing.
One, the lighter gravity might make waves easier to generate and sustain.
Second, there may have been a heavier atmosphere at one time, filled with the stuff of volcanoes. That may have taken a while to escape Mars and while it was there might have generated some waves.
Three. I don't have any "three". I'm out of guesses. Don't have a "four" or "five", either.
You're on your own. Gonna have to find someone who knows what they're talking about.
Arf