California launches earthquake early warning system it calls best in world

A visitor takes a photo of a crack in the ground following recent earthquakes near Ridgecrest, California, in July. Scientists say the earthquakes that hammered the Southern California desert near the town of Ridgecrest last summer involved ruptures on a web of interconnected faults and increased strain on a major nearby fault that has begun to slowly move. | AP

Reuters

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Oct 18, 2019

LOS ANGELES – California rolled out the nation’s first statewide earthquake warning system on Thursday, designed to detect seismic waves and alert residents through a mobile phone app even before the ground starts shaking.

Gov. Gavin Newsom, who urged Californians to download the MyShake app on the anniversary of the devastating Loma Prieta earthquake on Oct. 17, 1989, boasted the program was more sophisticated than early warning systems already used in Mexico and Japan.

“The price of admission to live here is preparation,” the governor told a news conference in Oakland overlooking the freeway bridge built to replace one that collapsed during the Loma Prieta quake, which killed more than 60 people in the San Francisco Bay Area.

“If millions of people (download the app) we will have points of contact, the ability to crowdsource information the likes of which no country in world has advanced,” Newsom said.

Newsom said that the California Earthquake Early Warning System, which uses hundreds of seismic sensors to detect fast-moving seismic P-waves from major earthquakes, could give residents up to 20 seconds before the shaking starts.

That time could be used to shut off gas or utility transmission lines or open elevator doors, he said.

P-waves, which travel through the interior of the Earth, arrive before surface waves and at a higher frequency during a temblor. Many animals are able to feel P-waves, according to the U.S. Geological Survey (USGS).

In general, communities farthest away from the epicenter of a quake would receive the most advance warning.

Already, the Bay Area Rapid Transit (BART) system in and around San Francisco has connected the early detection network to its rail service to automatically slow down its trains, and reduce the risk of a derailment in the event of a major quake.

The MyShake app, which was designed by University of California, Berkeley, seismologists and engineers, will initially alert users to earthquakes of a magnitude 4.5 or greater in their area.

Warnings are based on a computer program called ShakeAlert operated by the U.S. Geological Survey that analyzes data from seismic networks statewide, calculates preliminary magnitudes, and then estimates which areas will feel shaking, according to the governor’s office.

Japan developed the world’s most advanced earthquake early warning system after the 1995 Kobe earthquake, based on the same principles of physics as California’s.

Officials in Los Angeles County in January introduced a “ShakeAlertLA” mobile phone application that can transmit an early warning to residents who have installed the app, giving them extra seconds to take cover before a major quake hits.

The 6.9 magnitude Loma Prieta quake struck during a national broadcast of the 1989 World Series and experts have said the lighter-than-normal traffic because of the baseball game may have prevented a greater loss of life.