The time listing for your post indicates to me that regardless of the location of the person posting the note, the offical time listed is the U.S. Mountain Time listing.

So, the UTC correction for posts is always 7 hours (UTC = listed post time + 7). Or, I expect that if Daylight Saving Time is in effect there the correction would be 6 hours (UTC = listed post time + 6).

That would then provide some information regarding how to compare post times with earthquake times. With NEIS lists they look to me like they are usually listed with a UTC (Greenwich or Zulu) time.