Cathryn...I'm working west of offshore Malibu now (west of Pt. Dume)...more like offshore Port Hueneme (through south of the northern islands). My Nov 2006 JGR paper did cover offshore Malibu, but I generally work on long-term fault slip over millions of years, although we then compare it to younger stuff, generall work by others. To get last quake on onshore Santa Monica fault I would have to re-read Dolan et al. I think there it has been thousands of years ago. Geotechnical people have some trouble finding much evidence for a surface quake on the onshore Malibu Coast fault in the last 10,000 years (although I've seen papers in the past that had some evidence for (small?) slip. But, the large Santa Monica-Dume fault remains offshore there. Using an old grid of higher resolution seismic reflection (acoustic) data I located a good location for coring either side of the fault to roughly date last quake on that strand and passed it on to USGS collaborator a couple years ago. Just by length and downdip width of this fault system, it is likely capable of a M7+. You just stick fault area into an equation...let's see, what's that reference...Of course, an earthquake can break just part of the fault so the next one might be M1, 2, 6, whatever. But, we are talking about the maximum when we say 7+. There may be numbers on this in Dolan et al. 2000 (GSA Bulletin?).

The Santa Monica-Dume fault dips about 45 deg beneath the mainland (beneath the Santa Monica Mountains) so they shaking on land there would be worse than if the fault was vertical (given that it is a few km offshore).
Chris
Chris