Preparing for the Big One

 By Peter Ward

In July 2019, two earthquakes hit Southern California within days of each other, reminding the local population of the massive geological threat hanging over them: the “Big One”…

On July 4th – America’s Independence Day – a 6.4 magnitude earthquake hit Ridgecrest, a town north of Los Angeles, CA. The next evening, the same area was shook by a 7.1 magnitude earthquake. There were no serious injuries or damage to infrastructure, but the earthquakes have caused people in the state to think about their safety plans should another one hit. California is particularly prone to earthquakes because the state sits on the San Andreas Fault. A fault is an area where two tectonic plates come together, and in California the land where the Pacific Plate and the North American plate meet extends around 800 miles through the state. The fault has three sections, each with varying degrees of earthquake risks, but the most dangerous part of the fault is the southern segment, which runs within around 35 miles of Los Angeles. California has witnessed around 70 major earthquakes since tracking began in 1812, and some of them have been devastating. Luckily, the largest earthquake to hit the state occurred when it was still sparsely populated. That was in 1857, when a 7.9 magnitude earthquake struck California, with the epicenter at Fort Tejon. Only two deaths were recorded; if it were to hit today, the destruction would be devastating.

An aerial view of the San Andreas Fault in California (James Balog, Getty Images)

The rarer the stronger

“That kind of earthquake, on average, happens every 100 to 150 years“, explains Jason Ballmann, communications manager at the Southern California Earthquake Center. If a similar sized earthquake were to hit today, Ballmann reports estimates of 1,800 to 2,000 deaths, with significant damage to buildings and infrastructure. There have been several devastating earthquakes since Fort Tejon. One in 1906 hit San Francisco, causing 3,000 deaths and over $500 million in property damage. A 6.9 magnitude earthquake centered on Loma Prieta killed 63 in San Francisco and the East Bay area, and in 1994 the Northridge earthquake killed 61 and caused $15 billion worth of damage. This history has led to calls for increased safety awareness in the state.

Safety instructions

The Southern California Earthquake Center advises those caught in an earthquake to do three thingsdrop, cover, and hold on. “Whenever the earth starts to move, you should drop onto your hands and knees, cover your head and neck, and hold on until the shaking stops”, says Ballmann. This advice can be modified depending on where people are when the earthquake hits. For example, Ballmann says those on public transport should bend over at their waist, cover their head and neck, and hold on to something like a chair or a pole. After an earthquake like those that took place in July 2019, organizations like Ballmann’s see an increase in inquiries. 

Computer Simulation of an Earthquake by the California Academy of Sciences

“We see a lot of people coming to our website, calling in, and having lots of different inquiries; sometimes they just want to talk with somebody”, he explains. “Access to information or access to talking to someone is really consoling to a lot of people—just to have that validation that they just felt something that was traumatic or stressful and they’re not alone”.
When an earthquake does strike, one of the major causes of fatalities are fires that break out afterward. Of the 1,800-2,000 deaths predicted in the next “Big One”, Ballmann says half will be from fire. One important way people can guard against this is to have a plan to turn their gas off in the aftermath. “If you smell gas after an earthquake, get an adjustable wrench and turn it off”, he says. “If you don’t know how to do that, now’s a good time to Google around, ask a neighbor, ask a family member, or call the utility company”. (Ballmann adds that they don’t recommend people actually practicing turning their gas off, as they would need to call the utility company out to turn it back on).
In addition, there are other common sense ways to avoid fires, such as having wind-up and battery-powered torches on hand so there’s no need to light any candles after an earthquake. For people living in certain areas of the world, earthquakes are a dangerous inevitability. But with the right planning, they don’t need to be so deadly. “Everything is preventable”, affirms Ballmann. “The only thing we can’t prevent is the earthquake itself. But all the effects of an earthquake we can absolutely prevent”.

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about the author
Peter Ward
Business and technology reporter based in New York. MA in Business Journalism at Columbia University Journalism School 2013. Five years experience reporting in the U.S., the U.K., and the Middle East.