The frequently tremulous city of Los Angeles is now providing residents with a heads-up before the Big One (or the Not-So-Big-But-Still-Potentially-Dangerous One) hits via a newly launched smartphone app.

Available as a free download for iOS and Android, ShakeAlertLA is the first app of its kind to be made publicly available in an American city. The technology, which only provides early warnings for earthquakes and aftershocks with a magnitude of 5.0 or greater, doesn't kick in that far in advance — after all, earthquakes aren't exactly predictable. Once a quake has started, the system is triggered and an Angeleno's phone will light up with an all-caps push alert and sounds that last from several seconds to over a minute depending on the location of the quake's epicenter. These few crucial seconds of awareness before a major earthquake can mean everything and, ultimately, help to prevent injury, death and property damage.

Once installed, the app, which harnesses ShakeAlert technology developed by United States Geological Survey (USGS) with the support of several key collaborators, will work only within the confines of Los Angeles County. ShakeAlertLA doesn't necessarily need to be on at all times for an alert to come through, although a phone's location function must be activated — a feature that's raised privacy-related concerns from some.

In seismically unstable Southern California, speed is key

It may come as a surprise that ShakeAlertLA is the first earthquake early warning system for the general public in the United States given how seismically active huge swaths of California are — not to mention the entire West Coast and Alaska.

As the Los Angeles Times details, cities including Mexico City, Taipei and Tokyo have had sophisticated — but often false alarm-prone and not always foolproof — seismic alert systems in place for some time now.

The delay in implementing such technology in Southern California largely boils down to the fact that the faults that produce tremors are much closer to major urban areas than they are in, for example, Mexico and Japan. In addition to the installation of a considerable number of sensors that trigger the alert system, scientists simply needed more time to fine tune an app that would be truly effective in a scenario where a few seconds — not a couple of minutes as might be the case in other seismically active locales — make all the difference. Securing funding from the Trump administration to advance the work of the USGS, an agency that's essentially been stalled by the ongoing government shutdown, was also an issue.

Writes the L.A. Times:

Earthquake warnings work on a simple principle: Seismic shaking travels at the speed of sound through rock — which is slower than the speed of today's communications systems. Sensors that detect a big earthquake that starts at the Salton Sea and has begun to travel up the San Andreas fault could sound an alarm in Los Angeles, 150 miles away, before strong shaking arrived in the city, giving Angelenos perhaps more than a minute to prepare.
The further a quake's epicenter is from cities, the more warning residents there can receive — perhaps a minute for a temblor that begins more than 100 miles away. But quakes centered much closer could leave time for only a few seconds of warning, requiring the technology to render almost instantaneous decisions to be helpful.

"Here, especially in Los Angeles, where many of the faults are right under our feet, we need to be as fast as possible with a warning," adds John Vidale, a professor of seismology at the University of Southern California. "We really need to tune our systems for speed."

LA Mayor Eric Garcetti unveils ShakeAlertLA app 'Angelenos should have every chance to protect themselves and their families when there's a major earthquake,' says Mayor Eric Garcetti, whose office helped craft an early earthquake warning app for the public. (Photo: Mario Tama/Getty Images)

A life-saving heads-up before the ground starts to rattle

Available in both English and Spanish, ShakaAlertLA quietly became available for download on Dec. 31 following a lengthy beta testing period spearheaded by project partner AT&T that kicked off in 2017. The telecom giant worked closely with both the USGS and the office of Los Angeles Mayor Eric Garcetti in tailoring the app while the Annenberg Foundation provided a bulk of the financial support — via a $260,000 grant — needed to tweak and perfect the fledgling app in the development stages. Additional financial support came from the Mayor's Fund for Los Angeles.

Per the Times, after its first year the app will cost $47,000 annually to maintain.

"Earthquakes are a fact of life in Los Angeles, a challenge we'll always have to face. That's why early earthquake warnings must also be a fact of life — on our phones and on our tablets the very moment they're available," said Wallis Annenberg, president and CEO of the Annenberg Foundation, in a press statement. "The ShakeAlertLA app is an extraordinary breakthrough, an early warning system that's literally at our fingertips."

Garcetti officially debuted the app, which he had vowed to release by the end of 2018, at a City Hall press conference held on Jan 3. He reiterates the importance of a warning that arrives even 10 or 20 seconds before the ground starts to buckle and sway "can make a big difference if you need to pull to the side of the road, get out of an elevator, or drop, cover, and hold on."

ShakeAlertLA is very much considered a pilot project — an open-source work in progress that the USGS eventually hopes will be adopted by other California cities as well as in Washington and Oregon. The USGS already has ShakeAlert sensors in place in both these states — all that's missing is a public-facing app customized for at-risk locales.

"What we learn from this expanded pilot in L.A. will be applied to benefit the entire current and future ShakeAlert system," says USGS director James Reilly.

The last earthquake with a magnitude of over 5.0 to have a major impact on the greater Los Angeles area was the Northridge earthquake. Centered in the north-central San Fernando Valley roughly 20 miles northwest of downtown L.A., the 6.7-magnitude tremor — followed by thousands of aftershocks including two measuring at a magnitude of 6.0 — battered the region early in the morning on Jan. 17, 1994. At least 57 people were killed and thousands more were injured. Reported property damages soared as high as $50 billion, making the Northridge quake one of the costliest natural disasters in U.S. history.

More recently, a 5.3 tremor centered 85 miles west of downtown Los Angeles near Santa Cruz Island — the largest of Southern California's Channel Islands — on April 5, 2018. While the powerful rolling quake rattled nerves, it was too brief, too deep and centered too far offshore to inflict significant damage on L.A. or in neighboring Ventura and Santa Barbara counties.

As for San Francisco, which was rocked by a deadly magnitude 6.9 earthquake in 1989 and is long overdue for another major tremor, the Guardian notes that officials in the Bay Area are closely watching the roll-out of ShakeAlertLA.

"Due to the proximity of our fault lines, the San Francisco Bay Area only has few seconds of warning with the current earthquake early warning technology," says San Francisco Department of Emergency Management spokesperson Francis Zamora. "San Francisco is monitoring the pilot program in Los Angeles and looks forward to evaluating the results of the program."

Matt Hickman ( @mattyhick ) writes about design, architecture and the intersection between the natural world and the built environment.

Los Angeles debuts first early earthquake warning app in U.S.
Developed by the U.S. Geological Survey, the technology 'aims to reduce the impact of earthquakes and save lives and property.'