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25 Years After Loma Prieta: Bay Area Infrastructure Is Safer, But Still on Shaky Ground

More than $22 billion in infrastructure upgrades have built a metropolitan area that is far safer and far more resilient than before.

Loma Prieta damage San Francisco
A worker surveys the damage caused by the fire in San Francisco's Marina District after the Loma Prieta earthquake struck.
FEMA News Photo
(MCT) — If the Loma Prieta earthquake happened today, Buck Helm might have survived his Nimitz Freeway commute to watch his two youngest children grow up. Donna Marsden could have finished fixing up her Victorian home. Delores Stewart could have cheered on her beloved Oakland A's.

Twenty-five years later, the freeways and bridges that collapsed have been rebuilt to stand up to a quake even more powerful than the 6.9 magnitude Loma Prieta.

More than $22 billion in infrastructure upgrades have built a metropolitan area that is far safer and far more resilient than before. It's a testament to the power of long-term planning, borne of the ashes of the tragedy — 25 years ago Friday.

An extensive Bay Area News Group survey of our infrastructure offers much reassurance: Major water pipes are now designed to bend, not break. Bridges and overpasses can better support us. Gas and power lines are safer near fault lines. Hospitals are sturdier.

But our readiness to recover from the Big One gets far from a perfect score -- more like a C-plus, say experts who study quake preparation around the globe.

"A lot has been done," said Stanford civil engineer Anne Kiremidjian. "But to get a B, there's a lot more to be done.

"Our entire region is a very complicated system, and it all has to function together."

Decades of improvements buoy hope that while the Bay Area's $535 billion a year economic engine might sputter, it would eventually recover.

But the newspaper's analysis shows significant "lifelines" — BART's tunnels under the bay and through the Berkeley hills, the Golden Gate Bridge, highways, local roads and utility distribution lines — have yet to be upgraded. After a 7.0 or worse quake on the Hayward, San Andreas or Concord faults, it could take months, even years, for some systems to be fully restored, experts say.

And the status of private systems is unclear; telecom companies and refineries, for instance, insist on privacy that makes their preparations a mystery to Bay Area emergency planners.

[Support column failure and collapsed upper deck on the Cypress viaduct of Interstate 880. Photo courtesy of the U.S. Geological Survey.]

Our population has surged from 6 million to 7.7 million. Our economy now holds one of the nation's highest concentrations of wealth and is a center of innovation. And the next earthquake to challenge our more complex and interdependent urban lives may not rupture in the remote Santa Cruz Mountains. It may be underneath our feet.

If the Big One ruptures we could face up to $200 billion in total residential and commercial property damage, according to Menlo Park's Risk Management Solutions, which assesses earthquake risk worldwide. By comparison, losses from Hurricane Katrina totaled $120 billion.

Nature would never swallow whole something so colossal, concrete and wildly ambitious as the modern San Francisco Bay Area, said Kiremidjian.

"I can't imagine it being left in shambles. I can see the Bay Area pulling itself together and rebuilding," she said. "But by losing some of our infrastructure, we can lose some of our economic base."

Loma Prieta killed 63 people, injured more than 3,700, destroyed 366 businesses and 11,000 homes and caused $6 billion in property damage. The collapse of the Nimitz Freeway in Oakland was responsible for 42 of those deaths.

California quakes no longer tend to kill large numbers of people, because new building codes are more rigorous. But catastrophic damage to utilities, hospitals and transit systems? That scares away people and businesses. Once they leave, they tend not to return.

Such post-quake economic casualties can be seen in other earthquake-devastated places.

The Japanese maritime center of Kobe was once one of the world's busiest ports. Since a 7.2 earthquake in 1995, it has been unable to regain its status.

How will the Bay Area cope after a similarly devastating quake?

"If we compare ourselves to other parts of the U.S., the San Francisco Bay Area and the organizations that manage the infrastructures that cross the fault have done quite a good job in trying to retrofit," said Patricia Grossi of Menlo Park's Risk Management Solutions, which assesses earthquake risk worldwide.

Five main priorities

There are five recovery priorities, identified by experts: Power, water, communications, fuel and transportation:

Power network more durable. While the deadly San Bruno pipeline explosion exposed the danger of PG&E's aging and degraded pipes, the utility says since Loma Prieta it has installed earthquake-resistant electrical equipment, springlike metal gas transmission lines and automatic shut-off gas valves in fault areas. After San Bruno, the company has been upgrading pipelines throughout the region.

However, thousands of miles of small gas distribution pipes are being replaced slowly. So broken gas lines may ignite fires as they did in Napa.

Water system upgrades almost complete. The Santa Clara Valley Water District, East Bay Municipal Utility District and the San Francisco Public Utilities Commission are strengthening major tunnels, improving pipeline joints and rebuilding dams. But thousands of miles of smaller distribution pipes still pose a challenge.

Questions remain about telecommunications. AT&T and Verizon, two of the Bay Area's largest cellphone providers, say their systems are seismically up to date but won't reveal how their cellphone systems could be affected in a worst-case quake scenario.

Emergency mobile cell towers and operations centers can be trucked into a disaster zone. However, those services have rarely been tested in disasters affecting a wide geographic area.

A collapsed wall from Napa's 6.0 earthquake in August cut power at AT&T's downtown building housing cell service and 911 dispatch. Its backup generator was not working and the entire operation ran on battery power until another generator was brought in.

Uncertainty over fuel. All East Bay refineries are at risk in a major Hayward Fault quake, especially pipelines that cross fault lines, according to a 2010 study. But the Bay Area's five refineries are private and tell the public little about planned or completed seismic work. The companies assert that their facilities, all within strong shaking range of the Hayward and Concord faults, are up to date, but for competitive reasons they won't discuss specifics. All meet California requirements to prevent catastrophic releases, but the state does not require them to assess the risk of shutdowns that would limit fuel production, according to Contra Costa County Hazardous Materials Director Randy Sawyer.

Big fixes to bridges and overpasses: The newly constructed Benicia-Martinez and Bay bridges are the region's most seismically safe, but questions surfaced about the Bay Bridge's structural integrity. All Bay Area highway overpasses have been retrofitted, and construction on 401 smaller street bridges is more than 80 percent complete.

The newly opened fourth bore of the Caldecott Tunnel should be open for emergency vehicles within hours of a quake. The new Tom Lantos Tunnels at Devils Slide will withstand a major quake.

Overall, water, electricity, gas, and telecom providers have set up some emergency mutual aid networks.

Much work still to do

But transportation still ranks high among the biggest projects left on the Bay Area's to-do list.

BART's Berkeley hills tunnel is expected to collapse where it crosses the Hayward fault if a major quake strikes in that area. A 2002 study found a less than 5 percent probability of a quake occurring at the exact moment a commuter train was in that section.

Last year, technical advances led BART to explore replacing the tunnel's rigid liner with a "slinky" version, said Tom Horton, project manager of BART's Earthquake Safety Program.

"It's a very difficult, very slow retrofit to do the work around existing trains."

Also still at risk is BART's 6-mile long Transbay Tube. The agency thought it was finished with retrofits of the tube connecting San Francisco to the East Bay. But the structure needs a thin steel liner to keep it from flooding. That's expected to be completed no earlier than 2022, Horton said.

Among the Bay Area's many bridges, its most notable one — the Golden Gate — is also its most dangerous. A retrofit that began in 1997 might be finished in 2021.

A worst-case quake would extensively damage the suspension bridge now, while the retrofitted ends would have only minor damage, according to a bridge district spokeswoman. The final span will be retrofitted to the strongest level.

And 1,425 miles of highway and more than 2,000 smaller roads have not been retrofitted because they are not a significant threat to public safety — but they could become impassable, experts say.

Danger looms at Delta

East of the Bay Area, the Sacramento-San Joaquin Delta is a critical concern.

The area around Sherman Island just north of Antioch is a chokepoint for railroads, petroleum and power lines, and telecommunication cables to the Bay Area. Those critical infrastructure systems are protected by 1,100 miles of fragile earthen levees — some more than 100 years old. A major earthquake could trigger many levee failures, allowing salt water to infiltrate the state's drinking water.

Finally, all these systems depend on each other. Telecommunication needs power. Power system repairs need fuel. Fuel deliveries need roads. If too many links break, the Bay Area's booming economy could falter.

"The Bay Area has shown over the past 25 years a willingness to act to improve the reliability of our systems," said Ezra Rapport, director of the Association of Bay Area Governments. "When residents know about risks, they have acted."

©2014 the Contra Costa Times (Walnut Creek, Calif.). Distributed by MCT Information Services.