Hi Petra. The largest recorded quake using the epicenter of this one plus a 20-mile radius was a 4.60 on 05/17/1995. The catalog for this area starts at 1973 and goes to present time. However just south of there, there was a 6.5 quake on 4/15/1898. The catalog for this area starts at 1735 and ends in 1974.

As to this small cluster leading up to something larger. Using the quake catalogs there was no indication that it happened in the past. Of course like everything else just because it has never happened in the past doesn’t mean it can’t happen in the future. Just that it’s not likely to.

As to the DD theory. I rather doubt it. Most likely it’s a good old tectonic strain build up and the rock (s) holding it back got tired and decided it was time to let go. Take Care…Don in creepy town.