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Earthquake Early Warning in California Shifts Closer

An early warning system for California earthquakes could soon get a much-needed dose of money, a state lawmaker announced today (Jan 28).
/ Source: OurAmazingPlanet

An early warning system for California earthquakes could soon get a much-needed dose of money, a state lawmaker announced today (Jan 28).

State Sen. Alex Padilla (D-Pacoima) introduced legislation to fund a California-wide earthquake early warning system during a press conference at Caltech. The technology for a warning system already exists, through a prototype called the California Integrated Seismic Network, but scientists need more money to take it public. Other earthquake-prone countries with public warning systems include Japan, Mexico, Taiwan and Turkey.

The estimated cost to create a public warning system is $80 million. This will cover adding new seismic monitoring equipment and upgrading the state's existing network, as well as public outreach and education, said Lucy Jones, senior adviser for risk reduction for the U.S. Geological Survey (USGS), one of the monitoring network partners. "If we were building it from scratch, it would cost $650 million," she said.

Padilla added, "If you think about the lives we can save, the injuries we can reduce, and the billions upon billions of damages associated with every large earthquake, the system would more than pay for itself."

It would take from one to three years to fully launch the new system, Jones said.

Hope for more funding

However, Padilla's bill has no funding source within the state's budget, which is only now recovering from years of billion-dollar deficits. He hopes to identify a funding source by August, he said. The project also needs federal funding, Padilla said. Private groups have stepped in to help: The Gordon and Betty Moore Foundation kicked in $6 million in 2011 for the prototype.

"I'm moving on the state funding piece because I don't want to wait for the federal government. We ought to deploy it sooner rather than later," Padilla said.

There is a 99 percent chance of a magnitude-6.7 earthquake or larger in the next 30 years in California, according to the U.S. Geological Survey's most recent forecast, released in 2008. But the state's been relatively quiet for the past two decades — college students born and raised in the Golden State have never lived through a catastrophic earthquake.The last big shaker, the Northridge quake in 1994, killed 60 people and caused about $13 billion in damage. [ The 10 Biggest Earthquakes in History ]

"We should do this before the next big earthquake," said Caltech seismologist Egill Hauksson, one of the project leaders. "Then we will not miss the opportunity of saving lives," he told OurAmazingPlanet.

How earthquake early warning works

The warning system relies on the speed of light to outrun earthquake waves, which travel at the speed of sound, Hauksson explained. "It's like lightning and thunder. You see the lightning first, and hear the thunder later."

Here's how it works:

California is dotted with a dense network of sensitive seismic monitoring equipment called seismometers. When an earthquake starts, the nearest seismometers — and there are almost 1,000 in California — detect ground shaking and send electronic signals at the speed of light to computers that rapidly analyze the strength and location of the quake.

The early warning system relies on the time delay between two earthquake waves. The first wave to emerge from an earthquake, called the P-wave, is an acoustic, or sound wave. It may make a slap or a bump as it passes, but doesn't cause much shaking. The second wave out is an S-wave (sometimes called secondary waves), and they travel at half the speed of the P-wave — about 1.8 miles (3 kilometers) per second. The slower S-wave is the destroyer, the source of heavy shaking during an earthquake.

A computer can figure out the earthquake's size and location from the P-wave, and send out a warning signal before the damaging S-wave arrives. [ Video: Earthquake Early Warning System Demonstration ]

The signal arrives a few seconds to a minute before shaking, depending on the distance between the earthquake epicenter and the user's location, said Doug Given, the USGS early earthquake warning project coordinator. The primary users will be emergency personnel, hospitals, nuclear reactors, trains, factories and schools, Jones said. However, the signal will be publicly available, as in Japan, where programmers have created custom signal apps for phones, Hauksson said.

The prototype in place today works best for smaller earthquakes, and needs to be improved so it has fewer false alarms and can perform better during major quakes, such as those expected on the San Andreas Fault, Hauksson said. A recently published study suggests that California could experience a statewide earthquake, with the fault ripping apart for hundreds of miles.

"This is a starting point," Hauksson said.

The early warning system is a partnership between Caltech, the USGS and the University of California, Berkeley.

Reach Becky Oskin at Follow her on Twitter @beckyoskin. Follow OurAmazingPlanet on Twitter  @OAPlanet. We're also on  Facebook  and Google+.