The Newport-Inglewood fault is not the only one to worry about...it is not even the most active one....the Palos Verdes fault cuts right through Long Beach Harbor, and has a 3 mm/yr rate of right-lateral slip (McNeilan et al. 1996 (?))(compared to Newport-Inglewood, which has about 1 mm/yr (??)).Also, the Compton thrust is sitting down deep underneath...I am working on the offshore projection of that structure...the fault system that is creating Palos Verdes Hills anticlinorium, which extends uninterupted for 45 km and may be about 60 km-long over all (work with KB in the oil patch and others). And, if you are sitting on a deep sedimentary basin, there will be strong ground motion from more distant quakes (Olsen, Archuleta et al.)...but this motion may be more of a problem for taller buildings (Heaton? 1995?)...Now that I've added to your worries...quakes on the blind Compton system are probably pretty rare...could be thousands of years between them...
Chris