My whole life I've been hearing about the ‘Big One’ that is about to hit California. “Any day now,” they said. You know, the earthquake that will be so large that California will split off and fall into the ocean. 

And, so far, that really hasn't happened. Sure, there has been a couple of really big earthquakes (6.7 in Northridge in 1994, 6.9 in Loma Prieta in 1989 that impacted the World Series), but not, you know… the ‘Big One!’ 

California's earthquake hazard stems primarily from two volatile faults, the San Andreas and the San Jacinto. According to new research, stresses along these faults are the highest they’ve been in the last 1,000 years.

Earthquakes typically occur along the boundaries between tectonic plates. These fracture zones, or faults, accumulate stress as the plates slide past each other and become locked. Eventually, so much stress builds up that the plates suddenly slip, releasing all that stored energy in the form of an earthquake. The longer it’s been since the last big earthquake, the more stress may have accumulated along the fault.

The last major earthquake to affect the Los Angeles region was the Fort Tejon quake of 1857. With a magnitude of 7.9, it remains one of the largest temblors ever recorded in California. It’s been well over a century since this event, so scientists are concerned that the San Andreas Fault System could produce another major quake any day now.

Scientists are quick to say their research does not predict when the next major earthquake could rock Southern California, nor does it show that such an event is necessarily imminent. Rather, it offers a clearer picture of the region’s seismic hazard. This critically stressed fault system could rupture at any time, so communities need to prepare for the worst-case scenario.