Canie,
I also saw the 6:24pm time and I am assuming that it was wrong in light of the 6:11:12 PM at a depth of 0 feet recorded by the USGS. That would make it the time of the blast. I thought it might be close enough to the fault line to incur creep or other deforming stress. It would be interesting to check the neighborhood for signs of movement in sidewalks, roads and curbs. If gas was smelled before the blast, I would assume some movement in the area might have been enough to break the pipe or a weld.
Bob