None of those locations are near Fordo. It is located at 34.866, 50.997. NNE of Quom in the ridge below the dry lake bed. In 1973, I witnessed the Blue Angles doing a show near the Airbase just to the west of there.
Indeed, there was ZERO seismic activity within 100 miles of Fordow on the day in question, or any date near the day in question.
Well... that was my point. HOWEVER, the real problem was that I listed the data from JAN 21, 2012, instead of JAN 21, 2013.
I goofed big time. PJ-COMIX responded to me and listed the correct data in another post, showing seismic activity on that DATE and in that LOCATION.
Bottom line, it appears that there was some kind of explosion.