I may be buying an old victorian house that has a riverrock foundation, unfortunately I live in california and we are prone to earthquakes. I somewhat understand the basics of retrofiting a new concrete foundation to the existing river rock foundation, but I do not understand all of it. I know how to frame and pour the concrete next to the river rock, but how do I attach the new foundation to the old? Bolts? rebar? Are there any tips or websites I should look up?
You should contact your local government's Building Inspection Office and see what they have to say about that issue. This isn't really a DIY thing. They may be able to furnish you with do's and don'ts and some information on the mechanics of such an undertaking.
I agree with BUD siesmic loadings with regards foundation reinforcement and retrofit is something that should be looked at by a professional. Without the proper analysis and calculations you cannot be sure that it will actually help in the case of a quake. In the case of earthquakes sometimes too much reinforcement is actually a bad thing.