Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: Earthquake magnitude affects how much damage is done in an earthquake. A larger earthquake damages more buildings and kills more people than a smaller earthquake. But that's not the only factor that determines earthquake damage. The location of an earthquake relative to a large city is important. More damage is done if the ground shakes for a long time. Answer: magnitude
What general property of an earthquake is used to describe its relative strength?