Related to a paper I am editing for the lead author...I went into the 3D software, where I have all the earthquakes from 1930 to 2004 from Hauksson...near where the M5s occurred in 1979 and 1989, and spun the volume in 3D. As all the other times I have zoomed in and looked at these quakes, which I think have been relocated (Hauksson, 2002...data are available online in SCEC data center), the earthquakes are just a cloud...they do not seem to define any faults. The question is, how much of this is lack of precision in the locations (a lot were just stuck at 6 km depth), and how much is real distributed deformation through a volume of crust. My/our structural/tectonic interpretations here suggest distributed faults, block rotations, etc. One question is whether this area of high seismicity is capable of a very large earthquake (I think some nearby faults are, like the Santa Monica, and maybe the Compton-San Pedro Escarpment). But, do the right-lateral Palos Verdes and San Pedro Basin faults produce large earthquakes here (meaning, in the high 6 range or a little higher that would be expected from their length...).
Chris