The “Big One”: How could this affect the central coast?


It has been over 100 years since the 1906 earthquake that caused severe damage to San Francisco. Since then, Californians have long expected another “Big One” to strike along the San Andreas Fault.

Based on seismic history and current seismic cycle data, it is widely predicted that the next “Big One” will hit Southern California.

According to Cal Poly geology professor John Jasbinsek, since earthquakes do not follow a strict cycle, it is difficult to predict when exactly an earthquake may occur.

Jabinsek said paleoseismologists have speculated that the next “Big One” along the San Andreas Fault will have a magnitude of about 7 or 7.5, which is slightly lower than the magnitude of 7. , 9 from the San Francisco earthquake of 1906.

“It would still be a devastating event in the southern part of the San Andreas fault,” said Jasbinsek.

Of course, the local damage would depend on the epicenter of the earthquake. If an earthquake occurs in the Bay Area, the impacts on the central coast would be lower, but if it were in the central valley, the impacts could be much greater.

As for the potential damage from this hypothetical earthquake, Cal Poly geotechnical engineering professor Rob Moss said damage to the ground, liquefaction and disruption of electricity are among the potential effects of ‘such a big earthquake.

Liquefaction refers to solid soil becoming more liquid due to the stress caused by soil accelerations during an earthquake.

According to Moss, the central coast and California as a whole have strict building codes intended to prevent collapses during an earthquake.

“In California, we have the best building codes in the world. And it is, it is double. You have to have building codes and you have to have an app, ”Moss said. “And so that’s part of the preparation, it’s long-term planning, good building codes, good enforcement, and then personal responsibility and reflection.”

In addition to building codes, San Luis Obispo County has an emergency plan in place.

But, San Luis Obispo County Emergency Services Director Scott Jalbert said it would take about 72 hours for regional, federal and state help to arrive after an earthquake.

“But probably the most important thing is that citizens need to know that they can be alone for up to three days and that they need to be prepared,” Jalbert said.

Other steps the county has taken to prepare include identifying target risks, key infrastructure, and ensuring hospitals have back-up generators.

Cal Poly also has its own Director of Emergency Management, Anthony Knight, who is responsible for planning, preparedness, awareness and response to any hazards that may affect the campus community.

“We need to do risk assessments and vulnerability to hazard assessments to determine what our threats are here at Cal Poly, one of them being an earthquake,” Knight said. “In California, it’s one of our main seasons: fires, floods, winds and earthquakes.

Cal Poly has its own emergency operations plan, and preparedness measures and information can also be found online at

Knight advises to prepare by storing food and water, as earthquakes can disrupt electricity and water lines.

To prepare an emergency earthquake kit, visit the San Luis Obispo County Preparedness website.

Editor’s Note: An earlier version of this story stated that the San Andreas Fault does not pass through San Luis Obispo County. In fact, it runs through the northeast section of the county.

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