Researchers say major earthquakes along the San Andreas fault in California occurred more frequently than scientists had previously thought. They say it’s a grim reminder that the "big one" could happen soon. Unfortunately, a standard home insurance policy does not cover earthquake damage.

New findings by University of California Irvine and Arizona State University researchers conclude ruptures in the Carrizo Plain portion of the fault, about 100 miles northwest of Los Angeles, occurred as often as every 45 to 144 years, with the last big one -- the magnitude 7.8 Fort Tejon quake -- occurring more than 150 years ago in 1857.

"If you're waiting for somebody to tell you when we're close to the next San Andreas earthquake, just look at the data," UCI seismologist Lisa Grant Ludwig, principal investigator on the study, said in a press statement.

The new findings, published in the September issue of Geology, contradict the accepted notion that major earthquakes on the fault occurred every 250 to 400 years.

A big quake would catch many residents off guard. Only 12 percent of Californians have earthquake insurance. The California Earthquake Authority provides about 70 percent of the state's earthquake insurance, which is sold through participating insurance companies.