Todd, There are many faults missing from that map...especially offshore. People that I work with and I have made 3D representations of many faults and provided them to the SCEC Community Fault Model (CFM), but they are not on the earthquake maps. The faults that caused the Northridge quake are in this model as a single surface. As Don suggested, to show a non-vertical fault on a map can be misleading because the top edge of the fault, which may be buried several km below the surface, may be 10 km away from the fault at, say, 15 km depth. So, if you show these faults on a map....you may live, or build your nuclear power plant (example, Diablo Canyon) directly above the part of the fault that will release the most energy in an earthquake....but the map shows the fault to be relatively far away...(Actually, when the designed Diablo Canyon, they were unaware of the existence of the offshore Hosgri fault, which dips beneath the plant. That cost the ratepayers, rather than the stockholders, $2 billion, I think, for the redesign.

Oh, yeah, back to Northridge...go to the link...that is the SCEC CFM. You will see 3D figures that include the Northridge fault...but won't be able to pick it out. You'd have to spend a lot of time downloading the free software and figuring out how to use it to run the model. I have not done this myself because I run the non-free software used to create the model..

There is a manuscript submitted for publication by Plesch, Shaw, et al. on this...I'm one of the many co-authors as a contributor of faults.
Chris

• SCEC community fault model