An aftershock is a smaller earthquake that follows a larger one, occurring in the same area. When a major earthquake strikes, the ground doesn't just shake once and stop. The earth's crust continues adjusting and settling, sometimes for days or even months afterward, producing these follow-up tremors.

While aftershocks are weaker than the main earthquake, they can still be frightening and dangerous. Buildings already damaged by the first quake might collapse during a strong aftershock. Scientists can predict that aftershocks will happen after a major earthquake, but they can't say exactly when they'll happen or how strong they'll be.

The word is also used metaphorically for any unsettling event that follows a bigger shock. After a family moves to a new city, the aftershocks might include starting at a new school or missing old friends. When a company announces layoffs, the aftershocks could be employees feeling nervous about their own jobs. In these cases, aftershock describes the ripple effects that continue after the initial impact of difficult news or change.