That morning, a magnitude 6.0 earthquake hit Napa Valley, causing electric and gas outages, damaging buildings, injuring more than 200 people, and leading Gov. Jerry Brown to declare a state of emergency.
For researchers at UC Berkeley, however, the quake wasn't a complete surprise -- they detected the event 10 seconds before it happened through ShakeAlert, an early detection and warning system that's giving officials a preview of capabilities that might someday be available to emergency services throughout the state, should adequate funding be located.
Early Earthquake Warning
Last fall, Brown signed a bill ordering the system's creation so that officials would have a chance to notify the public and shut down critical infrastructure prior to the earthquake's arrival. Though the bill received unanimous bipartisan support, the project has struggled to find funding, so far receiving about $10 million of the $83 million needed to finance the project for five years. But the earthquake in Napa could prove to be the relatively gentle warning that California needs to get the project funded.
“It performed as expected, but not as well as it could have [if] we had better instrumentation in the area,” Given said, adding that California still relies on an old network of sensors that need replacing and augmentation -- and to do those upgrades, its program needs funding.
“What we’ve seen in other countries that have early warning systems is that they built them after large killer earthquakes,” Given said. “In Mexico, after the 1985 earthquake killed 10,000, and in Japan after the 1995 earthquake killed 6,400 people. In China, they’re now seriously building systems based on when the China earthquake killed over 80,000 people, so it’s our hope that we can build our system here before, and not after, the big killer earthquake.”
And even just a few seconds' notice is enough time to make a big difference, Given said, and 10 seconds is enough to take a number of important actions. “The most obvious for the public is to drop, cover and hold on, which only takes two or three seconds to do," he said. "If you’re in surgery, it wouldn’t take very long to secure the patient and maybe stop whatever you’re doing, turn off a machine, or stop an elevator. Every small earthquake like this that brings earthquakes to mind and gets people remembering the hazard that we have here makes it more likely we’ll get the support we need to complete the system.”
State Sen. Alex Padilla, who introduced the earthquake early warning legislation, said everyone saw the value of an early warning system when it was proposed.
“What I’m hoping is yesterday’s event reminds us of the urgency with which we need the system deployed, sooner rather than later,” Padilla said, adding that while he recognizes people were hurt during this earthquake, it could have been much worse. “I shudder to think what the consequences would have been if the earthquake was at 3 o’clock in the afternoon on a Wednesday as opposed to 3 o’clock in the morning on a Sunday, and if the epicenter was in San Francisco versus Napa. Fortunately it was a minor impact for an earthquake of this magnitude, but we know the next big one, whether it’s in San Francisco or Los Angeles or anywhere else, it’s only a matter of time.”
Gas Leak Detection
The earthquake disrupted electricity service to 70,000 Pacific Gas and Electric (PG&E) customers in Napa and Sonoma counties, but the utility restored power to almost everyone the same day. PG&E also received hundreds of calls reporting the smell of natural gas, but reported that there was no major damage to its natural gas transmission and distribution lines -- and only 20 customers had lost gas service. Identifying leaks is made much easier today by leak detectors introduced in 2012 that are 1,000 times more sensitive than traditional detectors.
PG&E spokesperson Donald Cutler said that since rolling out the program, the sensors have been useful in detecting leaks quickly and more efficiently. In one field test, a large crew equipped with the new sensors was able to check 35,000 locations in 17 days and fix more than 2,200 leaks, a project that would have taken four months using traditional technologies and methods, according to PG&E.
And the Napa earthquake gave PG&E an opportunity to test the technology in an emergency setting. “It’s definitely been helpful,” Cutler said. “It’s more sensitive and works well. Everything that keeps our customers and communities safe is always something that’s useful to us.”
An early detection system would do little to protect gas and power infrastructure, but could give people a chance to get to a safer location or brace themselves. In April, Mexican agencies and citizens were notified of an impending 7.2 earthquake via the Seismic Alert System of Mexico (SASMEX), giving some cities as much as 74 seconds advance notice.
