RONG-GONG LIN II reports for the Los Angeles Times OCT. 17, 2019
At 5:04 p.m. 30 years ago today, the ground shook under the Santa Cruz Mountains.
It took about six seconds for the energy to hit Santa Cruz, about 15 to 20 seconds to get to San Jose and 30 to 35 seconds to get to the northern edge of San Francisco. As a World Series game was getting underway at Candlestick Park, the shaking began to collapse a portion of the San Francisco-Oakland Bay Bridge and flattened a double-decker section of Interstate 880 in Oakland.
In 1989, there was no way to warn residents that the shaking from one of California’s most destructive earthquakes was on its way. That robbed millions of people of precious seconds to prepare.
Officials aim to make sure that won’t be the case with a future quake. On Thursday, the California Governor’s Office of Emergency Services will unveil an app created by UC Berkeley that will give all Californians who download it on iOS and Android phones the chance to get earthquake early warnings from any corner of the state.
Authorities will also begin issuing quake early warnings through the Wireless Emergency Alerts system, offering text message alerts even for people who have not downloaded the app.
The unveiling of the new version of UC Berkeley’s MyShake app is a major achievement in the years of efforts to bring California an earthquake early warning system. Until Thursday, only people with the city of Los Angeles’ ShakeAlertLA app and physically present in Los Angeles County could get the alerts.
Richard Allen, director of the Berkeley Seismology Lab, said a few seconds of warning can give people time to drop, cover and hold on before the shaking begins.
A repeat of the 1989 earthquake could give perhaps 20 seconds of warning to the Marina District in San Francisco, which saw major fires, apartment collapses and deaths; the former site of Candlestick Park would get perhaps 15 seconds of warning, as it’s a bit closer to the epicenter; San Jose might get a few seconds. The city of Santa Cruz was too close to the epicenter and probably wouldn’t get a warning.
The idea of earthquake early warnings has been around for a while; even after the magnitude 7.9 earthquake in 1906, a proposal was printed in the San Francisco Chronicle for a system that would sense quakes and send alerts by telegraph ahead of the shaking.
One of the first practical tests of the concept in California came after the Loma Prieta quake. Scientists devised a system to use sensors near the epicenter in the Santa Cruz Mountains to radio in alerts to rescue workers searching for survivors and victims about incoming shaking 60 miles away. The idea was to get the rescue workers an alert about a significant aftershock before the shaking hit. The system was in operation for six months and sent 12 warnings.
Officials say that the MyShake app is a prototype and that there could be bugs that need to be fixed; it’s possible that warnings could be delayed or come late, and there is always the possibility of false alerts or missed warnings. But Allen said the app is now good enough that they’re confident it will save lives, and distributing the app more widely is more helpful than keeping it away from the public.
“We cannot promise you a perfect system,” Allen said, but based on tests, “the system seems to be performing reasonably well.” The MyShake app’s systems operate in the cloud, and it was built to scale up to meet demand.
