I'm sad to say that I put a little more work into this than I am prone to do, and have found that my wonderful cluster is grossly distorted by a gold-plated USGS array in Puerto Rico. I find they love to go places where it is sunny. :)
So, in formal terms, if you drew a selectivity plot of the area, you would find it exactly matches this cluster. So, 2's are detected close, then there is a ring of and 3's, and outside that you have 4's. That means the same amount of activity could be elsewhere, but we wouldn't see it.