PARKFIELD, Calif. (CN) — On a recent Saturday afternoon, the tiny town of Parkfield, California, was typically quiet, though a few people were outdoors enjoying a break from a long, rainy winter.

After a scenic drive along Vineyard Canyon Road, a motorcyclist from Paso Robles stopped for a bite at the Parkfield Café. A Shandon school bus driver strolled through town pulled by a pony (“We’re getting ready for our first show.”) And, at a small bridge crossing the Cholame Creek, a middle-aged woman in a red Tesla stepped out of her car for a quick selfie beneath a sign denoting the San Andreas Fault.

While Parkfield (population: 18) is a tiny town, that sign has a giant profile.

“When I take my students on a field trip there, they always want to get a selfie with the sign,” said Julian Lozos, assistant professor of geophysics at California State University, Northridge.

There are actually signs at each end of the bridge, which crosses the tectonic boundary (the San Andreas Fault) between the constantly moving Pacific and North American plates. More than anything, the San Andreas Fault’s reputation as a major mover and shaker stems from the 1906 San Francisco earthquake, which killed 3,000 people and — less importantly — provided inspiration for the 2015 action movie “San Andreas” with Dwayne “The Rock” Johnson. Yet, because it experiences a significant quake roughly every 22 years, Parkfield, located 220 miles south of San Francisco, is referred to as the Earthquake Capital of the World.

“It’s a pretty well-deserved title,” Lozos said. “It’s a big deal for earthquake science.”

One of the longest faults in the world — extending over 800 miles — the San Andreas is divided into three segments, each with a different degree of earthquake risk. While the northern segment leveled San Francisco, the central segment at Parkfield garnered the attention of earthquake scientists in the 1980s for one notable distinction: similar earthquakes with a magnitude 6.0 or greater had occurred with regularity here, with large events in 1857, 1888, 1901, 1922, 1934, and 1966.

“I don’t think there is anywhere else where we get magnitude 6 earthquakes in a limited area on such a frequent basis,” said Andy Michael, a geophysicist with the U.S. Geological Survey’s Earthquake Science Center. “Some people would argue that earthquakes happen randomly, and we found the one place in the world where it looked like it was on a regular basis.”

With that in mind, earthquake scientists, including Michael, descended on Parkfield in the mid-80s to conduct the Parkfield Earthquake Experiment. As the name suggests, the goal was to figure out how to predict when the next Big One might strike. To do that, the scientists installed a massive amount of instrumentation in Parkfield, collecting data on the Earth’s movement. Knowing how consistent the quakes had been, scientists even predicted — with a 90-95% confidence level — that a big one would strike between 1985 and 1993.

As national media picked up on the prediction, local rancher Jack Varian and his son John took advantage of the burgeoning earthquake tourism, building the Parkfield Café (slogan: “Be here when it happens.”) and the Parkfield Lodge (“Sleep here when it happens.”)

This bridge across the Cholame Creek marks the boundary between the North American and Pacific tetonic plates. Since it was built in 1936, quakes have caused the bridge to shift five feet, as can be seen in the bent railing here. (Pat Pemberton/Courthouse News)
This bridge across the Cholame Creek marks the boundary between the North American and Pacific tetonic plates. Since it was built in 1936, quakes have caused the bridge to shift five feet, as can be seen in the bent railing here. (Pat Pemberton/Courthouse News)

After a magnitude 4.7 earthquake struck north of Parkfield in 1992, scientists issued a more precise alert that a big shaker would hit within 72 hours, drawing media from around the country. But what scientists discovered is that you can’t really predict an earthquake. To do so, Michael said, would require installing sensors deep into the earth, every few inches.

The next big earthquake didn’t hit Parkfield until 2004. But it did provide an opportunity for study.

“As an experiment it was successful because we have good data,” Michael said. “It was not successful in saying now we have a way to predict earthquakes. Because we can’t control that. We can only learn what the Earth actually does.”

Today, the media attention on Parkfield has softened considerably, as has the USGS physical presence.  The café and lodge are still there, but Parkfield is frozen in time, surrounded by hills, mountains and thousands of acres of ranchland.

Amid those ranches, Cholame Creek, often near dry, is robust with water thanks to recent storms. Two coyotes playfully chase each other in a field off Vineyard Canyon. And near the one-room schoolhouse, a row of 17 mailboxes acts as the town’s post office.

“We’ve never been in business to make Parkfield a big town,” John Varian told the San Luis Obispo Tribune in 2022. “Everybody out here wants it to stay just the way it is.”

But earthquake tourism still thrives.

After Lozos moved from Washington, D.C., to Southern California to study music in 2006, he quickly picked up a book, “Finding Fault in California: An Earthquake Tourist’s Guide,” that detailed ways to travel the state’s quake towns.

“I went to Parkfield about nine months after I came to California,” said Lozos, who was studying at UC Riverside at the time.

Lozos was traveling along the San Andreas the following year when he was injured in a serious single-car accident along Highway 101. That near-death experience made him rethink his future, and he decided to pursue a childhood fascination.

“I’ve always been interested in earthquakes and volcanoes,” he said.

After finishing his masters in music composition, he eventually earned a doctorate in geophysics from UC Riverside.

While his current employer is located in a city that suffered a major quake in 1994 at the Northridge Blind Thurst Fault, Lozos said the San Andreas is a seismic standout.

“The San Andreas really is an outstanding fault,” he said. “It’s spectacularly visible. It’s so obvious from the window of an airplane.”

Although the prediction experiment is over, measurements continue in and around Parkfield. Near the Peach Tree Valley, roughly 30 miles from Parkfield, Josie Nevitt, another USGS scientist, studies what happens as faults slip near the Earth’s surface, which is especially important since that’s where our infrastructure — roads, buildings and bridges — exist.

“We want to understand when a fault slips, how that’s going to disturb all of those features,” she said.

She is studying a relatively straight section that features a lot of creeping — measurable movement near the upper part of the Earth’s crust — in between large earthquakes.

“This portion of the San Andreas Fault creeps really fast and prominently, so it’s a bit unique in that way,” Nevitt said.

Scientists can’t predict quakes, but they can look at probabilities and they can share information with engineers who design infrastructure. Meanwhile, the ShakeAlert early warning system can send alerts that an earthquake has begun with a directive to “drop, cover and hold on.”

“The strength of ShakeAlert would be giving people several seconds of warning,” Michael said. “The weakness is that the people who are right next to the earthquake would not get any warning.”

Part of what makes earthquakes scary, Lozos said, is that unpredictability.

And that’s not going to change.

“The best we can do is prepare ourselves for an earthquake by having emergency kits in our homes and accessible to us and knowing what to do in an earthquake,” Nevitt said.

Behind the Parkfield Café, a stage boasts a sign announcing “Parkfield Bluegrass Festival,” a popular annual Mother’s Day event. The San Andreas Fault might have first attracted Lozos to Parkfield, but as a musician who plays mandolin and fiddle, the festival also called to him.

“When I found out Parkfield has a bluegrass festival, I was, like — ‘No way,’” he said. “Two of my favorite things!”

Now he not only attends the festival, but he also gives festivalgoers a tour of the town’s history, with lessons about its earthquake relevance.

As for the next Big One . . . it has been 19 years.

“It could happen at any time,” Lozos said.

Because the instrumentation has remained, another one would allow scientists to compare the next one to the 2004 quake.

“It’s an amazing opportunity to look at a full earthquake cycle,” Lozos said.