The Story
California is in an earthquake drought.
It has been almost five years since the state experienced its last earthquake of magnitude 6 or stronger — in Napa. Southern California felt its last big quake on Easter Sunday 2010, and that shaker was actually centered across the border, causing the most damage in Mexicali.
Experts know this calm period will eventually end, with destructive results. They just don’t know when this well-documented geological pattern will shift.
“Earthquake rates are quite variable: We have a decade or two where we don’t have many earthquakes, and people expect that’s what California is always like,” said Elizabeth Cochran, seismologist with the U.S. Geological Survey. Eventually, “we’re going to dramatically see a change in earthquake rates.”
Scientists have been warning California of seismic dangers, be it the Big One on the San Andreas fault or catastrophes that could come from lesser-known faults, such as Hayward or Newport-Inglewood.
One reason for the urgent alerts: Memories of a truly destructive quake in many urban areas have faded. And with that, some fear, the urgency of pushing seismic safety has also faded.
Experts say California ignores these realities at its own peril.
“Along the main plate boundary faults, we are in a deficit of earthquakes in the last 100 years,” said Tom Rockwell, a San Diego State paleoseismologist. “At some point, that’s going to change. We’re going to have some big earthquakes.”