Hi Lowell. Today’s quake at Coalinga is within the aftershock zone of the 1983 Coalinga quake. Most of the aftershocks were north of this location with a few further south of this location.

Today’s quake is located on the Great Valley fault, which as you know is a thrust fault. This fault always comes to mind when I think of Petra’s “Deep, dark and ugly.” Just over the hill to the west of this fault is the New Idria thrust fault. It is felt that this fault is a part of the Great Valley fault. At present I don’t know of any quakes occurring on this fault in recent history. Just over the hill to the west of this fault is the San Andreas fault. Take Care…Don in creepy town