Don,

Very interesting stuff. Thanks for posting. This quake has always fascinated me because it was strong and occured on an unknown fault. Yet it seems to be rarely discussed and in the 30 year probability study for the bay area, the USGS seemed very confident in focusing on only the faults they know.

From what I gather, this quake was spread out on a bunch of different related faults rather than one defined one? I couldn't understand the terminology in the other post but it sounds like the quake began one fault and leaped to others? Collectively giving the 5.7 but as a stand alone none of them very significant? That was my interpretation.