Now, back here at home, a rude awakening for millions of people on the west coast. An earthquake delivered a strong jolt when it rolled across los Angeles early this morning. The 4.4 magnitude did not... See More
Now, back here at home, a rude awakening for millions of people on the west coast. An earthquake delivered a strong jolt when it rolled across los Angeles early this morning. The 4.4 magnitude did not do much damage. But scientists say, for the first time, a new warning signaled it was coming. Here's ABC's nick watt. Reporter: Bottles and cans flew off store shelves. Pictures fell from walls, glass shattered. And local anchors took cover. Earthquake. We're having an earthquake. We did have an earthquake. A fairly large one. I think the epicenter was under my bedroom. Reporter: A little kid told me he thought a monster was shaking his bed. No injuries were reported. And no major damage. But this was one of the biggest shocks to his L.A. Since the aftershocks of the northridge quake, which killed nearly 60 people back in 1994. I think it's good preparation for the real one that might be coming. Reporter: This morning, seismologists say a prototype early warning system worked for the first time, and gave them a couple of seconds warning. Two seconds can do you a lot of good. Just imagine if there was an alarm in an operating room so the surgeon had pulled the knife out of your chest before the strong shaking came through. Reporter: In Japan, another earthquake hot spot, such a system has been up and running since 2007. In L.A., they're still waiting on the funding to make it a fully functioning reality. Nick watt, ABC news, los Angeles.
This transcript has been automatically generated and may not be 100% accurate.