For the 30th anniversary of the Loma Prieta earthquake—the 6.9 tremor struck October 17, 1989 shortly before game three of the World Series between the Oakland Athletics and the San Francisco Giants—Curbed SF will feature quake-related coverage looking back at that fateful day, and what you can do to prepare for the next big one.
Although transportation isn’t the first thing people will worry about when the next big quake hits, it won’t take very long for the city to start thinking about how it’s going to maneuver hundreds of thousands of people to their homes or emergency services through a city that may have just lost some its most critical transit infrastructure.
Thirty years ago, the Loma Prieta earthquake, a 6.9 tremor that shook the Bay Area for 15 seconds, collapsed major freeways, froze air traffic, and, most infamously, hobbled access to the Bay Bridge.
“A serious result of a large-magnitude earthquake is the disruption of transportation systems,” notes the U.S. Department of Commerce, citing potential transit hazards like landslides, ground failure, and tsunami damage as just a sliver of the potential fallout from the next major seismic shift.
In theory, people will get around after an earthquake the same ways that they did before—but only as long as the city’s infrastructure remains intact to make that possible.
Here are how some locals moved around on that fateful day 30 years ago—and how our transit institutions plan to respond during the first moments after the next big one.
Muni is supposed to respond to an earthquake by maintaining something as close to regular service as it can in the minutes and hours after a disaster.
Immediately after a quake, Muni bus operators are required to pull over, and light rail vehicles will stop, literally, in their tracks. Trips won’t resume until the driver gets direct clearance—which might take a long time, especially if vehicles can’t communicate directly with central control and have to wait for inspectors to arrive and give the go-ahead in person.
Even so, San Francisco Municipal Transportation (SFMTA) protocol is to resume normal routes as soon as possible, although likely with some reroutes around street closures.
Drivers ”may pick up passengers who are not waiting at regular Muni stops [and] vehicles may be more crowded than usual,” the agency write in its earthquake preparedness guidelines, published in 2015.
Melanie Brooks, a San Francisco native who was 13 years old at the time of Loma Prieta, relied on Muni in the aftermath. She tells Curbed SF she remembers a long trip home to the Mission District on a bus that carefully navigated through four-way stops without traffic lights and paused to pick up often-harried passengers.
“Every time we got on the bus, someone would share news and it would be outrageous things like, ‘The entire Golden Gate Bridge fell into the water!’” she says. But Brooks adds that fellow commuters were helpful and supportive during the emergency, panicked misinformation aside.
So, what happens to Muni when a major earthquake knocks the power out?
“For short-term, localized power outages, we have generators,” SFMTA spokesperson Erica Kato tells Curbed SF. “For large-scale, prolonged power outages, we focus on our motor coach fleet, and prioritizing routes to continue service strategically and efficiently.”
Motor buses will replace inoperable electric vehicles, although there are limits based on coach and driver availability. Worryingly, the agency has struggled with driver shortages in recent years—and, of course, Muni’s facilities and communications may be damaged as well.
The good news for daily commuters is that, although the idea of being stuck on Muni during an earthquake sounds like a nightmare for many, you could do a lot worse than a city bus when it comes to taking shelter from the brunt of a major tremor.
SFMTA quake guidelines note that passengers should stay in the bus or train during and after a seismic event, with the vehicle providing an effective source of cover from hazards like debris and exposed electrical wires.
For most of 2019, BART commutes have started an hour later than usual, with the first trains rolling out at 5 a.m. But most riders would agree that the inconvenience is a worthy one: seismic-safety upgrades of the Transbay Tube, expected to continue through 2023.
“What we’re doing right now is an internal retrofit,” BART spokesperson Jim Allison tells Curbed SF.
“The tube, we estimate, is in shape for any kind of quake that comes along every 500 years or more, but for the sort of quakes that happen about every 1,000 years there’s concern that the current pumping system would not pump out the leakage in time for everyone to evacuate.”
Hence the upgrades. A good investment.
In the event of any earthquake, BART freezes until track inspectors confirm that it’s safe to resume service—except in the case of trains inside the Transbay Tube, located under the bay. BART instructs operators to continue through to the other side in the aftermath of an earthquake, partly so that panicky passengers don’t feel like they're trapped underwater.
Like Muni, BART should resume normal service as soon as possible. How soon that is depends on the severity of the incident.
For everyday shake-ups without red flags—e.g., no seismic alarms, no secondary alarms, no unusual conditions, and no reports of damage—Allison says that inspections are conducted fairly quickly.
But in the event of a large quake with warning signs like “seismic alarms, a failure of our training control system, or pump failure in the tube, and then preliminary reports of damage to the tracks,” the agency may have to evacuate stations and vehicles.
Last week’s mass PG&E-instigated power outages gave BART the opportunity to show off its robust electrical redundancies, with the agency pledging to have trains running through mass blackout zones and to keep the lights on with its own generators.
But an earthquake is more unpredictable. A major shaker could damage the electrical infrastructure on which BART relies. Of the 12 switching stations that provide juice for the trains, BART has enough capacity to keep things running if two go down. But if three or more shut off, that could seize up the entire system.
Normally when BART stations close without notice, the agency fields shuttle buses to make up for lost train service. But as Allison points out, “The reality is BART doesn’t own any buses.”
Transit partners, like AC Transit, help fill in those gaps, and in the event of earthquake-driven closures bus agencies may do the same. But quake damage might minimize the availability of those other transit resources, in which case BART would have to fall back on emergency services from the state.
San Francisco International Airport
San Francisco International Airport (SFO) spokesperson Doug Yakel says that 30 years ago the airport control tower stood up to the force of Loma Prieta from a structural standpoint. But it turns out there are more variables involved than just the integrity of the building.
“The tower withstood the quake on that day, but it had a lot of glass damage,” Yakel tells Curbed SF. He describes blown out windows and broken glass scattered along the interiors, meaning that the tower was, briefly, intact and operational but “wasn’t a place that was safe for controllers to occupy.”
Live and learn; today the tower is designed to prevent a repeat.
Despite the complexities of air travel, SFO might be the transit hub best suited to a quick recovery from a major earthquake. As Yakel points out, the necessary elements of an airport are deceptively simple.
“What’s the most basic airport consist of? A runway. That’s what you need for arrivals and departures,” says Yakel. “Terminals come closely behind,” but if need be—say, because the region is relying on aid coming in via the air to help the city recover from a disaster—a suitable place to land is almost all that’s necessary to keep at least some air traffic flowing.
SFO’s runways are engineered so that they can tolerate quakes up to a magnitude of 8.0, although air traffic must pause for runway inspections. The airport has two sets of parallel runways laid out in a cross pattern, so it’s unlikely that all four would end up damaged enough to be unusable—but of course, one can never be sure until the time comes.
If the tower survives a quake but communications aren’t working, SFO would employ rudimentary yet effective analogue solutions: a light gun is essentially a huge flashlight about the size and shape of a coffee can that communicates with planes via color patterns.
A steady green light means a plane is clear to take off or land, while a flashing red light will warn planes on the ground to clear runways and planes in the air that landing isn’t safe, and so on.
This solution is trickier in some circumstances than others: the Federal Aviation Administration (FAA) guidelines warn that, among other problems, “pilots may not be looking at the control tower at the time a signal is directed toward their aircraft.”
At the very least, the light system would be the ultimate fail-safe that doesn’t go out of commission.
Loma Prieta knocked both SFO and Oakland International Airport briefly out of commission, but nearby airports in San Jose, Los Angeles, and Seattle took in flights unable to land at the two airports.
Seattle and LA might not seem like nearby destinations in practical terms, but when the FAA mandates that planes keep enough fuel to reach alternate destinations, these are the impromptu landing sites it has in mind.
When the Bay Bridge was damaged 30 years ago—resulting in its immediate closure for a month and a day—ferry service across the bay became more important than it had in decades.
Thomas Hall, spokesperson for the Water Emergency Transportation Authority (WETA), tells Curbed SF that existing ferry infrastructure was meager at the time, describing “just four public ferry boats in the Bay Area.”
He doesn’t mean four ferry lines—he means four crafts for the entire network.
Other public and private vessels had to chip in to supplement ferry service after the quake. In fact, Hall credits Loma Prieta with renewing interest in water transit; these days WETA, which did not exist in 1989, has 15 boats with 5,000 combined seats that carry an estimated 1.5 million passengers per year.
If the bridge ever goes out again, expect those boats to be swamped with additional passengers and facing likely delays, necessitation go-to emergency plans to draft private boats into service.
Unlike air or land travel, ferry service has little to worry about in terms of infrastructure damage; bay waters should be fine no matter how bad a shaking the area takes.
The biggest risk would be to the ferry terminals themselves. If those facilities no longer function after a major quake, a temporary terminal, like the one at Chase Center, illustrates how they can be created on the fly. Setting up a temporary ferry terminal is not as difficult of a process as, say, opening up a new Muni or BART station.
The same emergency response float parked by the Mission Bay arena can replace a closed ferry site for the interim, and WETA may use it increase capacity at still-functional terminals to handle extra demand.
“Installing it quickly in time for the Warriors’ season actually helped us test our plan for using in the event of an emergency,” adds Hall.
Neither Lyft nor Uber responded to requests for comment about how they plan to perform in the wake of a seismic disaster.
In the past, Uber has sparked public ire when its “surge pricing” algorithm responded to the huge increase in demand during natural disasters and other emergencies by sending rates soaring.
To save face, the company took to suspending surge pricing during sufficiently grave situations, like during a 2016 explosion in New York City, but didn’t always apply this standard consistently.
In 2018, the company pledged to reform its ways by implementing a “global security center” based in Washington DC that decides how Uber service will react to emergency situations. Uber may put the brakes on surge pricing after an earthquake—or it may just suspend service altogether, depending on what the team in DC decides.
Starting in July, Lyft began touting its new disaster relief access program, which may offer free rides to designated areas in cities recently stricken by terrible circumstances.
Of course, that’s only useful if phones remains operable. In 2017, Government Technology magazine noted that “a sizable earthquake could leave millions without [...] cellphones or internet service.”
During an emergency tens of thousands of people will try to make calls all at once, possibly paralyzing networks. The Bay Area has never suffered a truly devastating earthquake in the age of cellular service, so how well Silicon Valley will be able to serve us after the big one remains to be seen.