Scientists are warning of a new earthquake danger in Northern California. They’ve discovered that two fault lines link together north of San Francisco, creating a new risk for the nearly seven million people living in the Bay Area. Some 1,200 emergency responders took part in an earthquake drill Thursday, and hundreds of scientists, engineers and politicians gather Friday in Los Angeles to discuss the next big quake, reports CBS News correspondent Mireya Villarreal.

Here’s what happens in the drill: A magnitude 7.8 earthquake hits California and the clock is ticking. National guardsman are working to pull a trapped man from an elevator shaft, while a specially trained dog searches for stranded survivors. This is meant to help emergency responders prepare for the real thing. CONTINUE