Animate geometrical waves in a canvas

Hi everybody!

I'm trying to animate some geometrical waves that came from a central point.

By now, I'm using a canvas and using the arc property to draw them. But now, I want to animate them and I find problems.

dropbox.com/s/wus1osezcq67rb1/waves.png

I think that the proper use of loops could be key to solve this but I'm not able to finish it by myself

Anyone could give a hand?

Thanks in advance!