LULU GARCIA-NAVARRO, HOST:
The LA area shook early Friday, thanks to a magnitude 3.5 earthquake centered near Compton. But on Thursday, Californians got access to an early warning system that could allow a heads-up of up to 20 seconds - just enough time to stop, drop and take cover. The early warning alert is available through an app called MyShake, developed in part by Richard Allen, the director of the Berkeley Seismological Lab. He joins us now from the UC Berkeley campus. Welcome.
RICHARD ALLEN: Great to be with you, Lulu.
GARCIA-NAVARRO: First things first, did the app alert users to that Compton quake?
ALLEN: So no. So that earthquake, as you said, was only a magnitude 3 1/2 earthquake. And so we only send out alerts when the earthquakes are greater than a magnitude 4.5. And then we only send out the alert to regions expected to see shaking intensity three, which means most people feel a bit of a jolt.
GARCIA-NAVARRO: And how does it work? What does it use to sense an incoming quake? And then what does it do?
ALLEN: So what underlines the system is a system called ShakeAlert. ShakeAlert is a system that has a - traditional seismic sensors across all of California. It detects the earthquake when it's underway. And then with very rapid algorithms, we analyze that data. And we determine the area that is likely to experience shaking. And so that's what creates the kernel of an alert. And then once we have that, the MyShake system takes it. It identifies the phones that are in - within a region that are going to feel shaking. And it pushes the alert out to those phones.
GARCIA-NAVARRO: Is there hope of increasing the time of the warning period to, say, minutes, hours, days? Is that something that you foresee might be something that science would be able to do?
ALLEN: So it's real important to understand that earthquake early warning is about rapidly detecting an earthquake that's underway and then pushing out an alert ahead of the shaking. So that gives us the limitation on the time - how much time is there between when an earthquake starts and when people might feel the shaking? Our best estimates are that we can provide a few seconds to a few tens of seconds of warning with both the technology and the science we have at our disposal today.
Now, in the really big earthquakes, that time can actually be a few minutes. And so, of course, the research continues. The development continues. And we can see whether we can increase that for more than just a few seconds to a few tens of seconds. We'll have to see. But what we cannot do is go beyond those minutes. So when we talk about a few days, now we're talking about prediction. We're talking about predicting when the earthquake's going to start. That's a completely different problem. We don't know how to solve that problem. And so I think most seismologists would agree that's unlikely in the foreseeable future.
GARCIA-NAVARRO: And obviously, California is not the only place in the world that suffers earthquakes. Is this technology available elsewhere in the world? Could it be used anywhere else in the world?
ALLEN: So there are just a few places that have early warning today. It's - Mexico, Japan and now California are the big ones. And the challenge there is that they have to have these traditional seismic networks that are expensive to run. And so that's one of the research pieces here with the MyShake app - is that, in fact, in every smartphone, there's an accelerometer, a sensor that can detect earthquakes. And so what we're doing is we're exploring the ability to also detect the earthquakes with smartphones. And if we can do that, then we could do earthquake early warning wherever there are smartphones. And there are basically smartphones wherever there are people. So the ultimate goal here is to actually be able to deliver earthquake early warning around the globe.
GARCIA-NAVARRO: And I assume you have the app on your phone?
ALLEN: Of course. I've had the app on my phone for quite some time. I've been very fortunate to be getting alerts for quite a few months at this point.
GARCIA-NAVARRO: Richard Allen is the director of the Berkeley Seismological Lab and helped develop a new earthquake early warning app. Thank you very much.
ALLEN: Great to be with you, Lulu. Transcript provided by NPR, Copyright NPR.