LOS ANGELES — When a major earthquake strikes, seconds count.
In the devastating 2011 Japan earthquake, a sensor embedded in the ground detected the first signs of movement and immediately sent out an alert at the speed of light. Within seconds, text messages warning of impending shaking went out to roughly 50 million people.
Many people in Tokyo, 200 miles away from the epicenter, knew the quake was coming before they felt the shaking about 30 seconds later. Trains were able to slow down or stop, and not a single car derailed.
This week, a group of California’s top geophysicists and seismologists announced an $80 million plan to create a similar earthquake early-warning system in California.
It would be the first such network in the United States and marks an ambitious new safety initiative by some of California’s top state and federal earthquake experts.
The U.S. is behind Japan as well as Mexico, Taiwan, Turkey and even Romania in creating early-alert systems. Last year, residents in Mexico City were warned shortly before the shaking from a 7.4 quake that began near Acapulco arrived.
Democratic state Sen. Alex Padilla is proposing legislation to create the statewide network. California already has hundreds of ground sensors measuring earth movement, but experts said another $80 million is needed to expand and upgrade the monitors. They said the system could be up and running in two years if funding is found.
An early-warning system could be particularly beneficial in Southern California, which is at risk of a major temblor on the San Andreas Fault. The San Andreas is located far enough away from metropolitan Los Angeles that officials believe residents would have up to a one-minute warning of the huge quake.
If a temblor erupted near the Salton Sea, for instance, underground sensors along the San Andreas would send off an alert to points north and west, covering population centers in Los Angeles and San Diego. Experts said this would give time to shut off utilities, prepare emergency response personnel and slow trains.
A study released in January was the latest of many to predict a catastrophic quake on the San Andreas. This report, for the first time, raised the possibility of a mega quake across the entire fault line that would be felt from San Francisco to San Diego.
Padilla said it’s time for California to build its own system, adding that $80 million is a bargain compared with the billions dollars in damage the system could prevent.
“Think of the lives we could save. The injuries we can reduce. And the billions upon billions of damage. ... If we can just reduce that by a small percentage, or a fraction, the system would more than pay for itself," Padilla said.
At a demonstration Monday at the California Institute of Technology, seismologists showed how the system would work. The simulation recreated the 1933 Long Beach quake off the coast of Huntington Beach. A person in Pasadena, 40 miles away, would have about 18 seconds to prepare if an alert was issued.
In the demonstration, scientists showed the earthquake waves moving toward Pasadena from Orange County as an alarm sounded with a computerized voice repeating: “Earthquake! Earthquake! Earthquake!"
Officials said the idea would be for people to install a quake warning program on their computers and mobile devices. If a large earthquake occurred, the warning would take over the screen. Alerts would also be tied to automatic systems that could tell elevators to stop, open fire house doors and flash notifications on freeways.
The early-warning system would build upon the existing California Integrated Seismic Network that produces online maps following quakes showing a quake’s epicenter. Officials said California already has almost 1,000 earthquake sensors across the state, but the network needs an additional 200 machines and upgrades to 400 stations in order for the system to work.
Researchers have already developed a prototype, but it is so fragile that it probably would fail during a large quake, said Douglas Given, the early earthquake warning project coordinator with the U.S. Geological Survey. And given California’s enormous number of earthquake faults, there needs to be more sensor stations.
But it remains unclear how much support the system has in Sacramento. California’s budget picture has improved since voters approved the Proposition 30 tax increases last year.
But some politicians have warned against additional spending. And earthquake legislation has generally fared poorly in the last decade, particularly proposals that would add costs for property owners. Quake experts said the lack of a destructive temblor since the 1994 Northridge quake has lessened the pressure for quake regulations.
“Once we get another large earthquake, I’m certain everybody would say, ‘We should’ve had it,’" said Thomas Heaton, a Caltech professor of engineering seismology.
Padilla said he is seeking funding from state and federal sources.
“It’s going to be a challenge. If it was easy, it would’ve already been done," he said.
The concept of an early-warning system is an old one. Japan developed one three decades ago so it could slow down and stop bullet trains before quakes hit.
In 2007, Japan rolled out a nationwide system alerting cellphone users.
The warning system works when sensors in the ground detect the first signs of earth movement, known as P-waves, that travel at the speed of sound. The more damaging shaking, called the S-wave, lags behind at an even slower speed.
Although people in Japan might only have received seconds of advance warning through TV, radio or cellphones, authorities have funneled the alerts to take action automatically, like sounding an alarm at construction sites to evacuate workers, ordering crane operators to lower their loads, and opening the doors in locked CT scan rooms to allow patients to exit safely before the shaking begins.
California’s earthquake scientists have long struggled to gain attention for an early-warning system. Until recently, researchers were only spending about $400,000 a year developing the technology; in 2011, they received a $6 million grant from the Palo Alto, Calif.-based Gordon and Betty Moore Foundation to continue work on it.
“We will have an earthquake warning system, but will it be before or after the next Big One?" Padilla said. “It ought to be before."