San Jose State University researchers say the San Andreas Fault is slipping faster than previously thought, and Kim Blisniuk says the rate appears to have stayed constant over a 10,000-year window. She said Californians should keep an earthquake preparedness kit ready.
Blisniuk said, "And so the great aspect of this work is that it is a rate of which the landform preserves previous earthquakes along the fault". She added that the rate is similar to the San Andreas Fault to the north in the north coast section.
Sanborn County Park findings
Blisniuk said the work at Sanborn County Park showed that the rate does not appear to decrease along the San Andreas Fault, but instead appears constant over the 10,000-year window the researchers were able to document. In a related look at San Andreas Fault Lines, the fault junction at Cajon Pass is also used to study how stress can build over long periods.
She said, "I don't think the idea that the slip rates are and constant along the San Andreas Fault, where we have studied, it is a big surprise to a lot of people. We just didn't have that data before."
California earthquake preparedness
Blisniuk tied the finding to risk in California, saying, "We know that we live on a plate boundary, and we are always surprised when we hear, 'Oh my gosh, an earthquake occurred in Japan or Colombia,' but we are going to have an earthquake in California, and we should be prepared". She also said, "So we do have historical earthquakes along this fault, and we will have them in the future".
Her advice was practical: "I always use the example of insurance. We always want auto insurance. We buy auto insurance, home insurance. We never want to use it, but it's there for us". She said, "And so, having an earthquake preparedness kit to prepare us for a potential disaster when an earthquake occurs will really help us deal with the trauma of having an earthquake."
Peer review and Bay Area context
The research has not yet been published or peer-reviewed. That leaves the work as an early look rather than a final paper, even as the finding follows a recent 3.9 magnitude earthquake on the Hayward Fault in Oakland and comes after the 1906 San Francisco earthquakes and the 1989 Loma Prieta earthquake along the San Andreas Fault zone.
For people along the fault in California, the immediate takeaway is straightforward: keep supplies ready now, because the researchers say the fault may be moving faster than earlier estimates implied, while the exact slip rate they measured was not stated in the available reporting.
