This was on the local news this morning. Apparently they get between 60-70 potholes per year, this one was just so exceptionally bad that they had to do emergency repairs rather than make do with maintenance during off hours. The problem seems to be the underlying concrete. It's decades old at this point so it doesn't really guard against subsidence in the asphalt. The upcoming announced repairs are to replace this underlying concrete on the runway with the pothole.