Glad to hear about your good luck.

When I was at the Prison, an alarm would sound, and we had 20 minutes to switch our boilers to #2 fuel before the gas was shut down. Happened about 4 times a year.

We live in seismic zone 1, the weakest, but we do have 'em occasionally, and the seismic monitors shut it down.

Part of it was shut down during Isabel.

A line rupture some years ago shut it down for days to a significant portion of the region.

I quoted the exception in the post linked, but when I was the AHJ, it was not going to be allowed, and with design review and acceptance, it still won't be allowed.