Aftershocks, those who live through major earthquakes often say, are worse than the main shock in their own way. At least the main shock took them by surprise and was over fairly soon, in less than a minute usually. But with aftershocks, people are stressed already, dealing with disrupted lives and cities. They expect aftershocks at any minute, day or night. When a building is damaged by the main shock, aftershocks can take it down—maybe when you're inside cleaning it up.