Thirty years after the Loma Prieta earthquake struck at 5:04 p.m. Oct. 17, 1989, scientists who were working at Menlo Park's U.S. Geological Survey offices that day can still remember where they were when the shaking began.
In a series of video interviews produced by the geological survey and recently published on YouTube, scientists shared their experiences of what happened, and how the 6.9-magnitude earthquake's legacy has shaped research and earthquake preparedness in the decades since.
When the ground shook
Now-retired seismologist David Oppenheimer was in a colleague's office at the USGS Menlo Park headquarters when he felt the shaking start. In a video interview, he said his mind instantly went back to a paper he'd published a few years back, predicting where the next earthquake might be, and he initially thought, "Maybe we were right."
But when it really started to shake, he continued, he figured he should probably skip the intellectual victory lap – especially when it became clear that the quake was stronger than what he'd predicted – and get somewhere secure. "I started to think, 'Maybe I should forget about papers and, you know, seismology and get safe,' so I got under a doorway," he explained.
Carol Prentice, a research geologist and a newer employee at the time, said she'd been stationed at an inner office at the Menlo Park headquarters without any windows. Though she wasn't certain which fault was to blame at the time of the quake, she took solace in knowing she was prepared by grabbing the flashlight she'd stashed away in her desk drawer, just in case.
Other USGS scientists were out of the office at the time of the earthquake and had to navigate the tumult away from their colleagues in Menlo Park.
Geologist Tom Holzer said that he was waiting to pick up dinner at a Burger King on nearby University Avenue when the shaking started. He said he saw his burger come out as the earthquake rolled through the building and people started evacuating the premises. He got out too, but not before claiming his food. "I realized if I didn't grab that hamburger, I wasn't going to have dinner," he recalled.
Retired seismologist David Schwartz explained that he was just sitting down with a glass of zinfandel at home in Walnut Creek, readying himself to cheer on the A's at the World Series when the quake struck. "Suddenly the house just went ... voom," he said.
A research opportunity
But in the immediate aftermath of the earthquake, which killed at least 63 people, hospitalized another 350, and caused between $6 billion and $10 billion in estimated property loss, these scientists explained, their minds were already brimming with questions as they quickly recovered from the shock and got to work.
Rufus Catchings, a research geophysicist, reflected that after he recovered from personal concerns about whether he'd survive the quake, he found the quake's impacts to be fascinating on a professional level. "Much of the damage was in San Francisco and Oakland, yet the earthquake was far to the south – southwest of San Jose. So that was a real, baffling thing to me: Why isn't there a continuum of damage? Why is it concentrated in certain areas and not in others?"
According to the USGS, recordings collected during the earthquake allowed researchers to show that the ground shaking was worse in the softer soils around the margins of the Bay, rather than territory with more solid rock found inland, which helped to develop code revisions aimed at boosting earthquake safety.
The USGS also founded the Bay Area Earthquake Alliance in 2009, the survey reports, which is a public-private partnership aimed at promoting earthquake awareness and mitigation in the region. It co-sponsors the annual "Great California ShakeOut," an earthquake-readiness exercise that involves nearly 10 million participants statewide.
Oppenheimer said that the quake triggered an uncomfortable discussion with the engineering community. Engineers, he said, called upon the earthquake researchers to focus more on helping them answer questions like, "How hard does the ground shake at a given magnitude at this location?" than on producing academic research, which had, in the past, been more of a priority at the Menlo Park offices, he explained.
Are we safer now?
While the scientists interviewed credit the earthquake with advancing the survey's seismic understanding of the Bay Area, they're split on whether the changes made since then have made the area safer.
Prentice said she feels that the Bay Area is much better prepared now than it was when the Loma Prieta struck due to proactive efforts in the areas of engineering, building retrofitting, emergency planning and community education and preparedness.
Oppenheimer added that information and forecasts from the USGS have been shared widely with PG&E, Caltrans, rail agencies, municipal water districts and sewage entities alike to help them mitigate the impacts of ground shaking in an earthquake. "Undoubtedly, that's going to result in less catastrophic damage," he added.
Schwartz said an estimated $72 billion to $80 billion has been spent on retrofitting buildings and strengthening infrastructure since 1989.
"We would be years and years behind in making these changes if we hand't had the occurrence of Loma Prieta," he said.
Catchings, however, expressed some doubts that things are safer now. "There are probably more people here than there were 30 years ago," he said, adding that there's also likely more infrastructure, and more infrastructure built on top of earthquake faults.
"I wouldn't say we're safer. I would hope that the population is focusing in on what can happen and trying to take some precautions for themselves," he added.
Watch the full interview series, less than 20 minutes, here:
Read a fact sheet from the USGS about the earthquake here.