California on Thursday — the 30th anniversary of the Loma Prieta Earthquake — became the first state in the nation to roll out a statewide earthquake early warning system.
Years in the making, the system is based on hundreds of sensors across the state that measure ground motion.
When an earthquake starts, the sensors pick up its early energy and send an instant signal to U.S. Geological Survey computers in Pasadena. Those computers then send an alert over California’s wireless emergency alert system, which also is used to send text message notifications about severe weather warnings and Amber Alerts, the messages authorities issue for child abductions.
Under the new system, anyone with a cell phone who hasn’t opted out will hear a loud tone, and a message will pop up on the screen telling them an earthquake is imminent and to “drop, cover and hold on.” The idea is to provide from a few seconds to 30 seconds of warning so people can get away from things that might fall on them, pull their vehicle to the side of the road or reduce the risk of injury in other ways.
Members of the public also can download a free app created by scientists at UC Berkeley called My Shake to their cell phones. The app provides early earthquake warnings from around the state, along with the ability to report the amount of shaking they felt.
“Today we are making a big leap forward, in terms of focusing attention on prevention,” said California Gov. Gavin Newsom at a news conference Thursday in Oakland near the Bay Bridge.
The statewide network of sensors, which is still being expanded, is called Shake Alert. It was developed by the U.S. Geological Survey, the California Office of Emergency Services, UC Berkeley and CalTech.
Although a few seconds of warning may not seem like a lot of time, experts say it can make a big difference. The alerts can trigger automated equipment to stop elevators so they don’t get stuck between floors of tall buildings, or open doors at fire stations so fire trucks can get out, or close pipeline valves to prevent chemical spills, or alert surgeons at hospitals to stop delicate operations.
“We can reduce the number of injuries,” said Professor Richard Allen, director of the UC Berkeley Seismological Laboratory. “We can reduce the number of fatalities.”
The alert system will be improved and expanded in the coming months and years, with programs to better alert teachers and students at schools when earthquake shaking is about to occur, said Mark Ghilarducci, director of California’s Office of Emergency Services.
Ghilarducci, who worked on search and rescue teams at the collapsed Oakland Cypress Structure in the 1989 quake, where 42 people died, noted that the farther people are away from an earthquake epicenter, the more warning they will receive.
He said the system, which so far only is in English, will be updated and refined by scientists and emergency preparation officials.
“It is not yet perfect,” he said. “We will continue to improve the system.”
During the Loma Prieta Earthquake, people attending the World Series game at Candlestick Park would have received approximately 15 seconds of advance notice from the warning system launched Thursday. Those farther north in Marin County would have received about 18 seconds of advance notice, and people in downtown Santa Cruz, right near the epicenter, may have received none or notice when the worst shaking already was underway.
Newsom recalled that during the 1989 earthquake that he was living in an apartment in San Francisco’s Marina district waiting to watch the Giants-A’s World Series game. When the building shook, he said he remembers car alarms going off and the ground crumbling as some homes collapsed nearby.
The Loma Prieta quake, a magnitude 6.9, was the most destructive in Northern California since the Great San Francisco Earthquake of 1906. It killed 63 people, injured 3,757 and caused an estimated $6 billion in damage. Centered on the San Andreas Fault in the Forest of Nisene Marks State Park in Santa Cruz County, it wrecked the Marina district, downtown Santa Cruz and the Cypress Structure in Oakland, along with a section of the Bay Bridge.
“It was a moment of pride and spirit, not just tragedy, seeing folks from all walks of life, neighbors, coming together,” Newsom said.
Japan and Mexico have had similar earthquake warning systems for years, following major quakes there that killed thousands of people. California and the federal government have been slow to finance a system on the West Coast, and much of the system — which is considered the most advanced in the world — was developed with funding from the Gordon and Betty Moore Foundation in Palo Alto. But in recent years public funding has increased.
Newsom said that $46 million had been spent on the entire network of sensors and alert system and that it will cost $17 million a year to operate.
The goal is to have 1,650 sensors installed on fault lines and around major urban areas in California, Oregon and Washington by 2021. California will get the most: 1,115. So far, California has 697 up and running, and Washington and Oregon have 285. Eventually, planners hope to expand it to many other states and countries.
“This is a good investment,” Newsom said, “a wise and appropriate investment.”
Some agencies, including BART, already have early versions of the system. BART’s alert system can slow and stop trains automatically if a large quake is imminent.
Tests of the system in Oakland in March and in San Diego in June were successful.
But in July when the 7.1 Ridgecrest Quake hit in the Southern California desert, the system did not alert people in Los Angeles, who were using an early version of it, even though they felt shaking, which sparked criticism.
The reason was that planners had set it to send an alert only after a certain amount of ground shaking, and that threshold wasn’t reached in Los Angeles.
Scientists since have updated the system to send alerts after quakes of 4.5 magnitude to people in areas where there is expected to be a moderate amount of shaking. The idea is to provide warning, without sending too many alerts every time there is a small quake.
Technically speaking, the system is set to send alerts to people who will experience a level 3 on a 1-to-12 scale that measures the intensity of shaking. At level 3 on the scale, called the Modified Mercalli Intensity Scale, people can feel shaking indoors that causes vibrations similar to a truck rumbling by.
According to the USGS, there is a 99 percent chance of a quake 6.7 or larger somewhere in California in the next 30 years, and a one-in-three chance in the next 30 years of a 6.7 quake or larger on the Hayward Fault.
To learn more about the early warning system, go to https://earthquake.ca.gov
Newsom urged people to prepare now for the next quake.
“If you don’t do it for yourself, do it for your spouse, your kids,” Newsom said. “Do it for your pets, for your neighbors.”
