Below ground, yet top of the mind

Last week, a swarm of tremors erupted beneath the Salton Sea...200 of them in all, all of them relatively small. And that raised concerns that a number of communities in Southern California were not ready for a big quake. A number of cities closed government buildings, including the city of San Bernardino, more than 100 miles away. It's City Council postponed their business and workers at City Hall were told not to come to work on Monday and Tuesday. 

We're also learning more about the seismic make up of the Salton Sea area and that some of these quakes are happening deeper below the earth's surface than previously thought.