Seismic risk calculations are mainly used for insurance purposes. The computer programs take all the seismic hazard inputs, and combine them with the known susceptibilities of structures and facilities, such as electrical power switching stations. The result gives probabilities for economic damage or casualties.
Seismic risk can be reduced by active social programs that improve emergency response, and improve basic infrastructure. You can improve your own situation through earthquake preparedness. Building codes are a classic way to improve seismic risk, but it takes a long time for any significant effect.
A special subset is urban seismic risk which looks at the specific issues of cities.