Glen,
The 1/18 quake is given as M5.08. I don't remember there being a M5 quake at this time (2 weeks ago). Also, note that it says "Real-Time solution: Not reviewed". Also, note that quality factor=C. So, I'd be suspicious (sp?) of this solution. I have not seen the statistical depth variance curves before, or at least have not noticed them. I suggest you check with John V, or maybe another seismologist who is working in the area, to see whether there are any catalogues that have quakes checked by seismologists within a week or 2. Actually, the PDEs, the ones from USGS/NEIC, tend to change over the course of the first week or so, But, I posted here that one quake...I think about M5 and in California, had 2 very different mechanisms.....the first motion mechanism was very different than the Harvard moment tensor solution.

Anyhow, yes, paying attention to detachment slip is probably a good idea: Mark Legg had some ideas on this. Seeber and Armbruster, using their relocated quakes, saw a detachment activate after the Izmit Turkey Aug 17 99 quake to the northeast...and that was where the also deadly Duzce quake occurred a couple months later. It is sort of a big deal for Southern California Earthquake Center types whether the strike-slip faults cut through the detachments: there are detachments offshore southern California from Los Angeles to San Diego that no doubt extend beneath the coast...extending before 5 million years ago, maybe still active offshore San Diego, otherwise reactivated as thrust faults ...for example, Oceanside thrust of Rivero et al Geology (which is considered by the state USGS as inactive, and there is some support for it being inactive, but I have my doubts. )

But, I can't make sense of 3 quakes vs some detachment, where I don't know where the detachment is...even if I did know where the quakes and detachment were, it is too much mental gymnastics to do the 3D geometry in one's head. If I was working on this area, I would construct a 3D representation of the detachments, and then use a 3D software to image seismicity as it occurs. I am set up to do this (I know how and have the software), but it would take me way too much time: it is more important that I work on the Palos Verdes structure. I suggest that you (Glen) get in touch with Dorsey and tell her what you are trying to do, in a concise email, and ask whether her group has done a 3D representation of the detachment, or at least the active part. Or, maybe it has already been done by someone using relocated microseismicity. You could ask Dorsey, or Magistrale, or maybe Vidale, who is working on relocated microseismicity in that area. Carena and Suppe have a paper where they use relocated microseismicity to define deep fault geometry in, I think, the San Bernadino area....don't remember how far south their work went....and most of my stuff is still in boxes so I can't find that article easily.
Chris