The main issue I would point out is that the distance to a fault could be important information when buying a home, however seismic forces are very unpredictable. In a seismic event the surface of the earth has liquid qualities in how it reacts. Because of this, underground conditions can be blocked or the force waves can be reflected to or away. Picture a rock being dropped in a shallow pool of water, the ring waves would look like how seismic waves move. Now if you place rocks in the pool you will see how seismic forces react with the interference that the underground conditions may cause. Seismic forces can reflect forces too or away depending on where in the fault the forces come from. Perhaps your property is located on the rock. So even the best research may not bring the results and protection you want. The 2 story apartment building that failed in the Northridge Earthquake of 1994 had and an identical building next door which was built by the same people at the same time and did not fail. I have inspected hundreds of homes damaged by earthquakes; a neighborhood can have both heavily damaged and non-damaged homes. Bottom line is that in an earthquake it is really hit and miss.
One thing you can do it make sure your home has as many seismic resisting elements as possible. An Architect or Engineer can advise on those measures.
Your local building department would be a great source of information for all regional hazards.
Curt V. Schultz, REALTOR - Architect
You can search the property address at http://myhazards.calema.ca.gov/ to check if a property is in a EQ Hazard zone.
You can also look up a property's FEMA Flood Maps here:
If you are really serious about a property I would consider a Natural Hazards Disclosure report from Disclosure Source, their Premium Report http://www.disclosuresource.com/order.asp
Does it matter if the property is in a Seismic Zone? Probably, and it probably matters what the size of the EQ is too!