What it looks like to me, but I may be wrong, is this. The lichen is growing out radially from where it first colonized, so it makes a round thallus. As the thallus ages, the center, which is oldest, dies for one reason or another. A new thallus starts in the center and grows out radially, and again dies in the center, repeatedly. Most likely the same species continues to start again in the center because some fragment of it survived, and is able to begin growth again. 

An interesting feature of the closer-up photo is that there is a yellowish crustose lichen competing for the rock surface on the right side. It has messed up that nice concentric growth. I am not able to look at the photo and continue this message, but I believe there is also an orange crust growing between the rings where that yellow crust is not growing. WHy doesn't it mess up the rings? Or is that just the rock color?

Lots of wonderment. Someone should do  a long term study.

best, daphne

(Bruce just beat me to it with Arctoparmelia as I was composing the following.) Yes - its quite an interesting phenomena which would be interesting to study. I was looking for information and didn’t find much, but see this link to a page which touches on it - Symbioses and Stress: Joint Ventures in Biology - Google Books. Arctoparmelia centrifuga is particularly adept at this manner of growth - Arctoparmelia centrifuga | Flickr - Photo Sharing! Ellie Stocker Wörgötter (I think) mentions how some foliose lichens disintegrate in the centre as their periphery expands. Crusts like Polycauliona verruculifera do that too - https://www.flickr.com/photos/29750062@N06/3277498629/   7 years growth of P. verruculifera  - https://www.flickr.com/photos/29750062@N06/5350175598/ Plants do this too - https://www.flickr.com/photos/29750062@N06/22143189365/

Probably not related, but I was looking in Jens Petersen's book, The Kingdom of Fungi, at photos of fungi in petri dishes (pages 32 and 33), some of which had neat zonate growth. Here's a photo of Cercospora kikuchii (not from Petersen - http://www.mycologia.org/content/102/6/1221/F1.large.jpg (Guess its common in fungi, e.g. Trametes versicolor.) Getting far from lichens, but pretty neat - http://www.boredpanda.com/microbe-art-petri-dish-agar-contest-van-gogh-starry-night/

I have fairy rings in my yard, I always figured the fungus was just expanding out from some beginning point and the mushrooms were out at the leading edge, because every year they seem to be a bit farther out.

A co-worker sent me the photos, they're from somewhere in eastern Washington. I'll have to see if I can go take a look for myself.