Patrolling the underworld from Menlo Park, USGS scientists await the Big One
The alarming numbers had been rippling across the Pacific to the Menlo Park offices of the U.S. Geological Survey all week, each one sending a kind of electric jolt through seismologist David Oppenheimer as his phone buzzed frantically with the latest news.
"When my cell phone lights up, and I see there's a magnitude 8 earthquake in Samoa, my first reaction is, 'Wow, people just died,'" Oppenheimer said. "I can tell from the depth, I can tell from the magnitude, and I don't have to see any more. It's kind of sobering."
A week before the 20th anniversary of the Loma Prieta earthquake, all was quiet along the fault lines that fillet the Bay Area. Houses stood erect on their foundations, traffic moved fitfully along retrofitted freeways, and life proceeded as if the violent spasm that shook the region Oct. 17, 1989, had never happened.
But not in Oppenheimer's subterranean world, where he can never stop watching his monitors, waiting for something horrible to happen here.
It was a busy week below the Earth's surface, and across the Pacific, a decidedly deadly one above it. For most people here, the memory of Loma Prieta was even more remote than the carnage in Indonesia, where a magnitude 7.6 quake leveled villages and left more than 1,100 dead. In American Samoa, 22 were killed by a tsunami triggered by a quake. And four days after that, a magnitude 6.6 quake struck the Philippines.
Meanwhile, Oppenheimer had just finished monitoring a swarm of more than 435 small quakes rattling the Owens Valley in Central California when his cell phone once again buzzed insistently.
As he read a text message on the screen in the palm of his hand, the seismologist made a low, nervous sound and said, "This is not good."
A magnitude 7.6 quake had struck nearly 6,000 miles away, off the Pacific island of Vanuatu, setting off tsunami warnings. This time the tsunami failed to materialize, and nobody died, but at the USGS it set off a tidal wave of questions. Did this string of massive quakes marching eastward across the Pacific mean that the Big One was heading toward California?
So many quakes
Oppenheimer runs the Northern California Seismic Network — an array of nearly 500 ground sensors, most of them deployed after the Loma Prieta earthquake shook the Bay Area out of its geologic torpor 20 years ago. If the region's spider web of major fault lines is forming a bull's-eye beneath our feet, he is among the scientists at the USGS most likely to know.
"You can't help but think that the waves go out, and it shakes the whole planet," Oppenheimer said. He wondered whether the Pacific quakes would be "the straw that breaks the camel's back? When Vanuatu got shaken by these other two or three earthquakes, what happened? That's a difficult question. And the answer is, I don't think so. But I don't know."
Fortunately, there's a lot more that earthquake scientists do know now. Though it was not widely understood at the time, the biggest and most important office in the USGS system was thrown into chaos during the hours immediately after the Loma Prieta quake. The power went out, then the backup system failed, and a generator managed to keep only a few computers running.
"It barely worked in 1989," recalls Oppenheimer, who came to Menlo Park in 1977. "The networking crashed, so it took two hours of frantically running extension cords around the building to get it working again. It was not a proud moment."
In those days, the USGS had a room filled with drum-shaped seismographs that translated ground movement into a homely scrawl on paper. This became such a staple of television's earthquake coverage that the Visitor Center still has one of the old machines, reverse engineered to convert a digital data stream to analog. "There's such an expectation that that's what we do," Oppenheimer said, "so we take a $50,000 instrument and dumb it down to something that looks like it was operating 30 years ago." Which it was.
Besides those drums, the only significant piece of monitoring equipment the USGS had in 1989 was a TV set, which led seismologists to incorrectly conclude the Loma Prieta quake's epicenter was near San Francisco, rather than Santa Cruz. It was nearly two hours before the computers rebooted and the scientists learned that their eyes had deceived them.
To avoid a repeat of the fiasco that followed Loma Prieta, the USGS now has banks of computers that process data from remote sensors and immediately put it on the Internet — a network that didn't exist in 1989. "We've made huge improvements in the rapid availability and processing of data," said Paul Spudich, a geophysicist at the Menlo Park office since 1979.
Adrenaline rush
The USGS is the largest civilian mapmaker in the world, and in the warren of bungalows where the Earth's crust is gently poked and prodded for clues to the next big shaker, the walls provide a constant reminder that it's a big world out there. And when discomforting data arrives from places like Sumatra and China, turning USGS scientists into "CSI: Magma" cops, people often get hurt.
"You really regret the price that people pay in earthquakes," says Spudich. "I think we'd all be very happy if they just stopped, or more realistically, if we managed to improve the infrastructure so that nobody got hurt. So that it was just an enjoyable thrill ride for everybody, as opposed to a life-threatening experience."
USGS geologist David Schwartz, who was also with the USGS when Loma Prieta struck, concedes he still can't suppress an "adrenaline rush" when a big quake happens. "I would not want to see a large earthquake on the Hayward fault," said Schwartz, whose home sits close to the fissure line. "But if it happened, I would be tremendously excited just seeing how right or wrong we may have been in our estimates of how buildings behave. If we turn out to be right, it gives us confidence to apply what we're doing here to other places. If it turns out we were wrong, well, then it's back to the drawing board."
Oppenheimer sees it much more starkly. He knows that if he doesn't prepare his data collection network for the next big earthquake, he will never get another chance. "It's not going to stop any of those buildings from falling down," he says, "but the next generation will benefit from those recordings. If I miss that opportunity, if those computers fall on their face, if we do something wrong and we don't acquire that data, it means waiting 150 years. That's a huge penalty for future generations. I worry about that."
Contact Bruce Newman at 408-920-5004.
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