In recent years, a camp has emerged that's more hopeful. It's pushed by researchers using satellites who say it may be possible to someday predict quakes from space and others who think they can tease out signals in rocks.
Mainstream seismologists remain skeptical about the claims. The two groups recently met in Los Angeles to start a dialogue.
Scientists have been trying to solve the riddle for decades. They've studied everything that might be a sign of an approaching quake including ground warping, weird weather and animal behavior.