Developers of ShakeAlertLA, a phone app connected to the US Geological Survey’s (USGS) earthquake early warning system sensors, said they would lower the app’s alert threshold.
“Our goal is to alert people who might experience potentially damaging shaking, not just feel the shaking,” said Robert de Groot, a spokesman for the USGS’s ShakeAlert system, which is being developed for California, Oregon and Washington.
The announcement came in the wake of two major earthquakes registering magnitude 6.4 and magnitude 7.1 that struck Southern California last week near Ridgecrest in San Bernardino County, about 154 miles northeast of Los Angeles, according to the USGS.
The app is designed to warn residents of an earthquake registering magnitude 5.0 or above, or one that could cause potentially damaging shaking in Los Angeles County.
Despite the size of the earthquakes, the tremors registered beneath the warning threshold in Los Angeles County.
“The tremors were well above magnitude 5,” de Groot told the Pasadena Weekly on Monday. “But the expected shaking for the Los Angeles area was level three,” he said, referring to a different scale used to assess damage.
A revision of the magnitude threshold down to 4.5 was already under way, but the shaking intensity level threshold would remain at four, which means even under the change Los Angeles County residents would not have received an alert.
De Groot said he fears that if there are too many alerts, people become desensitized to them.
“If people get saturated with these messages, it’s going to make people not care as much,” he said.
ShakeAlert would eventually cover the entire west coast and is about 70 percent complete, according to Gov. Gavin Newsom.
Eventually the system will send out alerts over television and cellphones, the same system used by amber alerts, to areas prior to earthquakes.
The state is partnering with the federal government to build the statewide earthquake warning system, with the goal of turning it on by June 2021. The state has already spent at least $25 million building it, including installing hundreds of seismic stations throughout the state, according to the USGS.
President Donald Trump has twice threatened to pull the funding to the project which is sponsored by one of his fiercest critics Rep. Adam Schiff (D-Burbank).
This year, Newsom requested $16.3 million to finish the project, which included money for stations to monitor seismic activity, and $7 million for education. The state Legislature approved the funding last month, and Newsom signed it into law.