Like all the previous titles in the SimCity franchise, the latest game—which is titled simply "SimCity"—there are a host of disasters for you to unleash upon your city. But in order to use these disasters, you'll first have to unlock them.
Unlocking each of these disasters comes with an achievement, which you may or may not care about, since the idea of leveling your city with a disaster should be more than rewarding.
To unlock the Earthquake disaster and achievement, you'll need to extract 100 tons of raw ore or coal. Once you do so, you'll be able to use the Earthquake disaster on your city whenever you feel like making your sims' lives that much harder.
Like all disasters in the game, earthquakes can occur naturally. They'll bring down buildings and start fires, so be sure to have a fire department in case that happens.