Living with California's Faults

Rick Gore
National Geographic - April 1995

At 4:31 in the morning on January 17, 1994, the earth's crust snapped 11.4 miles beneath the community of Northridge in Los Angeles. An immense slab of rock began to thrust upward along an unknown buried fault, shifting the San Fernando Valley eight inches and releasing a surge of energy approaching in power the 1980 eruption of Mount St. Helens. At that moment, 15 miles south in Santa Monica, Rob Wirtz, a firefighter, was sound asleep in his station house. Within seconds a shock wave from Northridge knocked the wall phone above Wirtz's bed off it hook and onto his head. It was an unwelcome wake-up call, not only for Wirtz but for everyone in L.A.

The 38-year-old captain leaped up and into the trousers and boots he keeps at his bedside and ran toward the station's garage.

"Things were shaking so hard I could scarcely get my pulled up," he recalls. Reaching the garage, Wirtz saw a 38,000-pound fire engine bouncing up and down.

"I looked out the garage-door windows and saw the lights of L.A. blacking out," he says. "I knew something big-time was going on."

The Northridge earthquake--the most costly in the history of the United States--had struck. And L.A. residents were experiencing what geologists warn may be a new era of disastrous earthquakes throughout California.

Near the epicenter in Northridge, Rosemary Sato jolted upright in bed as tremors slammed through her house with the deafening sound of a sledgehammer. "Who has such wrath?" she recalls wondering as the quake blew open her front door, knocked down the wall around her house, and tossed furniture around like toys.

In a neighborhood west of downtown L.A., eight-year-old Carlos Bejarano woke up to the flashes of power transformers blowing outside his family's apartment.

"I thought monsters were flying into my room," he remembers.

Fate struck more violently at the three-story Northridge Meadows apartment complex. An early rising resident, Steve Langdon, was about to make coffee when his building lurched eight feet. The top two floors then crashed down onto his first-floor apartment.

"A wall fell on me," he says. "I couldn't move my head. I was pinned against a bed for five hours with a collapsed lung, five fractured ribs, and a broken collarbone."

Meanwhile, 16 other apartment residents died. Thirteen were crushed in bed by the joists of the upper floors. David and Cecilia Pressman, who had been married for 51 years, died embracing each other.

As aftershocks rumbled, L.A. residents assessed their losses. The magnitude 6.7 quake killed 60 people. It destroyed or left uninhabitable more than 3,000 homes. It toppled ten highway bridges, closing three major freeways. Its spasms demolished part of a huge shopping mall in Northridge and collapsed seven concrete parking structures. Damage estimates exceeded 20 billion dollars.

By comparison, the 1989 Loma Prieta quake in the San Francisco Bay area cost six billion dollars. Of all U.S. natural disasters, only Hurricane Andrew in 1992 cost more--about 30 billion dollars. Still, the city was lucky. Striking in the predawn hours, the quake claimed far fewer lives than if it had hit with rush-hour traffic on the freeways, children in school, and shopping malls crowded.

Most are staying. "I'm in the music industry. I can't run anywhere," says Ron Fair, a senior vice president with RCA Records on Sunset Boulevard. Fair recently bought the house owned by 1950s TV stars Ozzie and Harriet Nelson. The Hollywood Fault runs right through his living room. Even though the Northridge quake did 150,000 dollars' worth of damage, he cites the estimate that the Hollywood Fault only breaks every few thousand years.

"I'll take my chances," he says.

Still, the cost of this earthquake--one insurance company lost 815 million dollars--creates fears about future catastrophes. It might have been worse. Stronger building codes, implemented after the 1971 San Fernando earthquake, prevented far greater damage to L.A.'s structures in the Northridge quake. Nevertheless, the tragic failure of the Northridge Meadows apartments underscores the need for better inspections.

"And this wasn't the big one--not even close," says attorney Joel Castro as we climb through the debris of the complex. The odor of rotting food surrounds us as we step over the rubble of wallboard, insulation, fallen joists, and twisted window frames.

"We haven't found any building in this project in which the interior partition walls were connected to the floors and ceilings," continues Castro, who represents earthquake victims and their survivors in pending litigation. "Plywood shear walls, or support panels, would have held this building up--if there had been enough of them. Whole lengths of some were actually removed to put in utility panels."

Among many other defects, Castro points out joist hangers that are only half the size called for in the building's design.

"I'm not sure how much insurance the defendants have," he says, "but I'm pretty sure we'll get all of it."

Defense attorney Allen Tharpe expects a settlement. "We maintain," he says, "that the shaking was so strong this building would have collapsed even if it were built perfectly."

In fact, the shaking was surprisingly intense. In some places the ground accelerated with a motion exceeding one g--the force of gravity. Most buildings are designed for much less than that. So the first news was good: Most structures performed well.

The bad news began emerging a few days after the quake. In more than a hundred steel-frame buildings--a common type of construction in buildings five stories and higher for the past 25 years--inspectors uncovered cracks in critical welds, flanges, columns, and beams. Even though some tests done in the 1970s showed steel welds could be unreliable, engineers had embraced welding technology, applying it to hundreds of billions of dollars of high-rise construction, not just in California but in downtowns and suburban centers across the country.

Now every structural I talk with tells me that even though no steel-frame building collapsed during the quake, the welds and connections between their beams and columns must be strengthened.

"Confidence in steel-frame buildings has eroded," says Tom Sabol, a member of a panel of southern California structural engineers studying the problem.

Engineers are still debating how to fix the buildings. Strengthening one connection costs $5,000 to $50,000. A major high-rise with a thousand connections would thus face staggering retrofitting costs.

"Most of those buildings will not collapse in a big earthquake," Sabol emphasizes. "But it's a risk, and people occupying those buildings should be aware of the risk."