Eartquake early warning system works.

[Isamu]

So last year in Japan we had this nation-wide earthquake early warning system set up on everyone’s cell phone. Since phone signals travel faster than earthquakes, it would (could) give you at least some warning.

Just now, an hour ago, a very large earthquake ocurred in Tottori ken. Everyone’s phone in my office went off at the same time saying that an earthquake was coming. (You get the warning whether or not your phone is turned off or in quiet mode)
about ten seconds later, here in Osaka, on the 14th floor, my building started creaking and swaying around like a boat adrift.

Anyway, that was my first real, live, test, and it works. Not sure that it will help me very much as I can’t do too much in 10 seconds - just get under my desk, which is what I would do even without advance warning.

[Isamu]

Update - Some damage done to structures, power outages but no injuries reported(yet).

[steatopygia]

Glad you and everyone else are OK (as far as you know). I wonder how much lag is built into the system?
For instance does a person have to actually push a button for the warning to go out or is it completely automated?

[Asimovian]

Also glad you’re OK. What DID you do with your ten seconds? How did the people around you react? Did you instantly know what the warning was?

[Machine_Elf]

@steatopygia

Glad you and everyone else are OK (as far as you know). I wonder how much lag is built into the system?
For instance does a person have to actually push a button for the warning to go out or is it completely automated?

The bullet trains automatically shut down in the event of a quake. The shaking spreads pretty quickly from the epicenter, so ISTM that the entire early warning system (not just for bullet trains) would have to issue warnings automatically.

Makes me think of this XKCD blog entry:

@Randall Munroe

I once heard a story (originally told by Kevin Young) about Gerson Goldhaber, who was a physicist at Lawrence Berkeley National Lab. He was talking on the phone with another physicist at SLAC near Stanford University near the end of the day on Tuesday, October 17, 1989. The SLAC physicist suddenly interrupted with, “Gerson, I have to go! There’s a very big earthquake happening!” and then hung up. So Gerson stepped out into a group of people in the hall, made a big show of yawning and checking his watch, then said, “Aren’t we about due for an earthquake?” Before anyone could respond, the Loma Prieta earthquake reached Berkeley, and he became a legend.

[JackieLikesVariety]

I think 10 seconds is much better than no warning - glad you are OK.

[Isamu]

@steatopygia

Glad you and everyone else are OK (as far as you know). I wonder how much lag is built into the system?
For instance does a person have to actually push a button for the warning to go out or is it completely automated?

As Machine elf says, it seems to be automated, according to the Press too.
The epicenter was about 150 kms away from where I was, and we all got the warning about 10 seconds (I think) before the waves hit us.

@Asimovian

Also glad you’re OK. What DID you do with your ten seconds? How did the people around you react? Did you instantly know what the warning was?

That’s the real question. Yes, we all instantly knew what it was. I say instantly but first there is an alarm, like a fire alarm at your phone’s full volume, then a second later a verbal warning that “earthquake!” “Take cover”. And that is repeated two or three times. I was having an after lunch nap on my desk, and was quickly awakened. But you are right Asimovian, no one took any evasive action. Everyone just sat there in tense silence waiting for it to hit us, without knowing the size of what was coming (the warning doesn’t tell you that important fact about how big the shockwave will be). Anyway, we are on the 14th floor, what are we going to do? It takes 5 minutes to run down the stairs but two minutes for the building to collapse. What would you do?

[Machine_Elf]

This video shows the speed at which earthquake waves propagated across Japan during the 2011 Tohoku quake. There’s a clock at the bottom-right corner. Quake happens at 5:46:23 UTC, and takes a good seven minutes to propagate all the way across Kyushu (the large island at bottom-left).

@JackieLikesVariety

I think 10 seconds is much better than no warning - glad you are OK.

Agreed, even ten seconds is useful; it’s enough time to assess your surroundings and start moving away from dangerous objects (e.g. heavy appliances, furniture).

Interestingly, I just learned that the age-old advice to head for a doorway is outdated:

@USGS

In past earthquakes in unreinforced masonry structures and adobe homes, the door frame may have been the only thing left standing in the aftermath of an earthquake. Hence, it was thought that safety could be found by standing in doorways. In modern homes doorways are no stronger than any other parts of the house and usually have doors that will swing and can injure you.

YOU ARE SAFER PRACTICING THE “DROP, COVER, AND HOLD ON” maneuver under a sturdy piece of furniture like a strong desk or table. If indoors, stay there. Drop to the floor, make yourself small and get under a desk or table or stand in a corner. If outdoors, get into an open area away from trees, buildings, walls and power lines. If in a high-rise building, stay away from windows and outside walls, stay out of elevators, and get under a table. If driving, pull over to the side of the road and stop. Avoid overpasses and power lines. Stay inside your car until the shaking is over. If in a crowded public place, do not rush for the doors. Crouch and cover your head and neck with your hands and arms. You should practice the “DROP, COVER AND HOLD ON” method at work and at home at least twice a year.

[Pleonast]

I’m hoping California gets our warning system working soon, rather than later.

@Isamu

(the warning doesn’t tell you that important fact about how big the shockwave will be)

Unfortunately, I don’t think it’s even theoretically possible to do that. Energy measurements take time, which is precisely what is in short supply in a warning system.

[Asimovian]

@Isamu

That’s the real question. Yes, we all instantly knew what it was. I say instantly but first there is an alarm, like a fire alarm at your phone’s full volume, then a second later a verbal warning that “earthquake!” “Take cover”. And that is repeated two or three times. I was having an after lunch nap on my desk, and was quickly awakened. But you are right Asimovian, no one took any evasive action. Everyone just sat there in tense silence waiting for it to hit us, without knowing the size of what was coming (the warning doesn’t tell you that important fact about how big the shockwave will be). Anyway, we are on the 14th floor, what are we going to do? It takes 5 minutes to run down the stairs but two minutes for the building to collapse. What would you do?

I spent basically my entire life in earthquake territory, so I think I’d instinctively duck under a desk or, if that wasn’t an option, brace myself in a doorway. But since I’ve never experienced having a heads-up, I was very curious about what you actually did under the circumstances. It’s very easy to assume that we’ll all respond appropriately in the heat of a big moment, but it’s rare that we actually find out the truth of it.