Is California Overdue For It's Next Big Earthquake?

UC DAVIS (CBS13) — It's a direct but cautious prediction from a local earthquake expert who cautions it's been fairly quiet on the continent recently.

Recent earthquakes have struck Ecuador and Japan.

Earthquake forecasting is controversial but has had success.

Professor John Rundle is a distinguished professor in the Departments of Physics and Geology at U.C. Davis.

"Our specialty here is the quantitative study of earthquakes, we simulate them in the computer and we look at the physics behind earthquakes," he said.

He's also an earthquake forecaster, and his data shows that things have been pretty quiet in California.

"In the 80s and 90s we had large earthquakes pretty regularly in California," he said. "We haven't had anything like that in 16 years and that's a little unusual."

Unusual because Rundle's data shows an earthquake cycle with about one large earthquake a year.

"There have been 81 earthquakes of magnitude 6 or greater in the California-Nevada region since 1933," he said.

The last one was the magnitude-7.0 Napa quake on Aug. 24, 2014, more than a year with nothing.

"There's a pretty high likelihood of something happening in the next year or two, magnitude-5 or larger," he said.

His data shows that with this so-called quake dry spell even the lack of magnitude-5s means there may be a dangerous build-up under the surface.

"We do know from statistical relations of earthquakes for every magnitude-6 there are eight to 10 magnitude 5s," he said. "So if you're not having 5's it means the earth is storing up energy that could be released in a major earthquake."