Hollister, California lies directly on the San Andreas fault, though it never experiences earthquakes. The fault is lubricated by a mineral that contains high amounts of talc. What this means is that water and certain minerals lubricate fault lines. The absence of these lubricants leads to violent dislocations in the earth as these faults relieve built up stress. We call these dislocations earthquakes. Right now, all we might be able to do with this knowledge is move cities at risk to areas which will not experience earthquakes based on their geology. (It's folly to build permanent structures (oxymoron) in a geologically unstable area. Gee, people are both stubborn and foolish.) The alternative is to drill into the fault and inject a talc-water slurry into it, thus lubricating the fault and possibly stabilizing the previously earthquake prone area. The issue is whether the earthquake mitigation engineering would cost more than other alternatives such as moving the city, or rebuilding it after the quake. One day such geoengineering will be routine assuming a cheap energy supply. A really cheap energy source and a lot of talc (baby powder) would be needed though.