California’s new earthquake early-warning system successfully sent out an alarm three seconds before a 4.4 magnitude tremor hit Pasadena.
While the quake caused little damage, it was felt over a large swath of area.
CalTech seismologist Lucy Jones reported getting the warning at her location seconds before the quake hit on Tuesday night.
Tuesday’s quake hit La Verne at 7.33pm but was felt from Ventura County to Orange County more than 100 miles away.
California’s new earthquake early-warning system successfully sent out an alarm three seconds before a 4.4 tremor hit Pasadena. Pictured is the shake map for the quake, showing that it moderately hit the city of La Verne, with a light effect in the Los Angeles metro area
CalTech seismologist Lucy Jones reported getting the warning (pictured) at her location seconds before the quake hit on Tuesday night
The amount of warning an area receives depends on how close it is to the earthquake’s epicenter.
‘Out of nowhere the room just started shaking,’ Ruben Estrada, who was in class when the quake hit at La Verne University, told KTLA.
‘Desks were everywhere, people were screaming. We were in a mad panic. But everyone made it out safely.’
The quake was followed by more than a dozen aftershocks and was the largest tremor in the Los Angeles metro area in three years.
Jones demonstrated how the early-warning ShakeAlert system worked. The system began beeping loudly to warn that it was approaching.
The sound became more rapid as it got closer and closer.
Many got the alert on a cell phone app called Quake Alert, whose goal is to send notifications to phones up to 60 seconds before a quake hits.
But the app is still in the testing phase, and not everyone got a warning on Tuesday night.
Many got the alert on a cell phone app called Quake Alert, whose goal is to send notifications to phones up to 60 seconds before a quake hits. Pictured is an example of what a warning message from the app would look like during an earthquake
CalTech University is one of the beta testers of the system, which is being developed by the US Geological Survey.
The early-warning system is meant to rapidly detect the beginning of an earthquake, estimate the level of expected ground shaking, and issue a warning, according to the California Integrated Seismic Network.
It works by detecting the first energy to radiate from an earthquake – known as the P-wave energy – which rarely causes damage.
The P-wave information can estimate the location and magnitude of the earthquake and provide warning before the S-wave – which causes the most damage – arrives.
While a few seconds of warning may not sound like much, it can be everything in a major earthquake.
This isn’t the first time the early-warning system has worked. San Francisco received an 8-second warning before a 6.0 magnitude tremor hit Napa in 2014 (pictured)
A crack running down the center of an earthquake-damaged street after Napa was hit
‘This is enough time to slow and stop trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments, and to take cover under a desk,’ according to CISN.
Airports, oil refineries, pipelines, schools, universities, city halls, and libraries along the West Coast are planning or already testing the system.
West Coast map shows the amount of advance warning time that might be available from an early-warning detection system during future earthquakes
California hospitals are testing the system to give surgeons enough time to remove scalpels from patients, while office buildings are being rewired to automatically bring elevators to the nearest floor when the warning sounds.
Condominiums in the state are also being rewired so that residents have enough time to drop and take cover, according to the Los Angeles Times.
This isn’t the first time the early-warning system has worked.
Scientists at the University of Southern California received a 10-second warning before a 5.3 quake hit near the Channel Islands in April.
And San Francisco received an 8-second warning before a 6.0 magnitude tremor hit Napa in 2014.
The USGS has been developing the early-warning system for years, but has struggled to find funding.
President Trump attempted to end federal funding for the program in one of his earlier proposals for the federal budget.
But Congress then approved a $1.3-trillion budget bill that included a $22.9million contribution to the system.
The USGS earlier promised it would issue limited public alerts from the system by the end of the year as long as funding wasn’t cut by the government.
It is hoping to later install more sensors in Washington, Oregon, and parts of rural Northern California.
Similar systems are already in full swing in Japan and Taiwan and are being tested in central and southern Mexico.