Earthquakehazardsmaps can be drawn up to highlight areas at risk.
Some countries practice earthquake drills, like we have fire drills in this country. 1st of September is earthquake drill day in Japan (which marks the anniversary of the Tokyo earthquake in 1923, that killed 156,000 people).
People should also know how to turn off their gas and electricity supplies to minimize the risk of fires, and should fasten down objects where possible.
Volcano hazard maps are drawn up to show areas most at risk from ash and lava – this means that some areas could be set up as no go areas where everyone has to move out.
And probably obvious advice for all natural hazards is for people to stock up on food, water and fuel, as well as knowing how and where to evacuate to.