Earthquake prediction: A work in progress

A lot of people in Los Angeles were angry that the city's operational Earthquake Warning System did not alert them to shock waves coming from Thursday's 6.4 magnitude shaker in the Southern California desert, 150 miles away. The explanation: L.A.'s system was set to send out alerts if expected magnitude there was magnitude 5 or higher which it never reached. It can easily be adjusted. Tom Vacar reports.