Geologists urge Californians to brace for 'The Big One'

Posted: Feb 15, 2018 7:50 AM EATUpdated: Feb 15, 2018 10:13 AM EAT

By Christina Favuzzi

Earthquakes are part of life as Californians. While it’s not unusual to feel an occasional minor tremor, scientists say it’s only a matter of time until a major quake rattles our state.

Now, local experts are warning residents to prepare.

Around the world, from the Middle East to Mexico, communities are digging out after recent life-shattering earthquakes.

In a matter of seconds, quakes crumble buildings and homes and even turn deadly.

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Though the images are devastating, local public works officials like Dave Flynn, San Luis Obispo County Public Works Deputy Director, look at them closely.

“We're in California. This is earthquake country,” Flynn said. “It's not a question of if, it's a question of when.”

Flynn says plans are underway to update several area bridges in the coming years.

The bridge at Avila Beach Drive over San Luis Creek will undergo retrofitting this year.

In Oceano, the bridge at Airpark Drive near the Elks Lodge is also slated for retrofitting in 2018.

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In 2019, the Lopez Drive bridge over the Arroyo Grande Channel will be upgraded.

County staff plans to update the bridge at South Bay Boulevard over Osos Creek in 2020.

“It just requires much deeper foundations,” Flynn said. “We'll have concrete shafts that will be drilled down at least 60 feet just to stabilize the bridge.”

If a big quake hits soon, Flynn says our coastal location could put us at an amplified risk.

“Oceano, around Morro Bay and the estuary, those would be areas that would be subject to higher earthquake forces as those areas tend to amplify the seismic forces,” he said. “There's less stability in the soil for the structures to be stable.”

The San Andreas Fault spans about 800 miles across California. A world-famous section of the fault runs through the Carrizo Plain National Monument at Wallace Creek.

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The irregular shape and sharp turns of Wallace Creek show that the ground has moved here in the past because of the San Andreas Fault and warn that earthquakes will happen again in the future.

Dr. John Jasbinsek takes his Cal Poly students to Wallace Creek and has them calculate the worst case scenario of a big quake on the San Andreas.

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“If you calculate that using some assumptions, but that are reasonable, hopefully, then it's something like 8.3 which has never been known to happen,” Dr. Jasbinsek said.

In a 2008 study, the U.S. Geological Survey found over the next 30 years, there’s a greater than 99 percent chance of a 6.7 magnitude or larger earthquake hitting California.

Geologists say it’s most likely the quake will originate in Northern or Southern California.

The so-called “Big One” would cause an estimated 1,800 deaths and 53,000 injuries, according to U.S.G.S.

“It would probably shake enough down here to scare you pretty good and I wouldn't rule out the weakest buildings having cracks,” Dr. Jasbinsek said. “When you've got minutes of shaking, that's got to be frightening.”

So, when will it happen? Geologists can’t say.

Current science only allows for broad probabilities, not exact predictions. Instead, the message is to be ready.

“Residents should anchor their shelves, their water heaters, and review their chimneys to make sure that they are stable,” Flynn said. “Make sure they know where their gas shutoff valves are in case of an earthquake as well as having an emergency kit containing first aid, water and food.”

“Losing sleep over it doesn't help anything,” said Dr. Jasbinsek. “It doesn't make these probabilities go down, doesn't make them go up, so there's a lot of uncertainty in life aside from earthquakes so you have to approach it the same way