A top seismologist is warning that another major earthquake is in our future, a big one that could devastate Southern California, from the desert to the sea.

Lucy Jones, of the U.S. Geological Survey says it's not a question of where but when a big quake will strike the Coachella Valley, sandwiched between the San Andreas and San Jacinto faults.

Jones says that region is long overdue, and the seismic clock is ticking.

Jones says a magnitude 7.8 quake or more could collapse major freeways, knock down buildings in Downtown L.A., kill thousands of people and cause hundreds of billions of dollars in damage.

Officials in the Coachella Valley say they're taking her warning very seriously.

 Source : ABC.com (News Video Included)