45 seconds is an incredible accomplishment. That’s a decent amount of heads up to get safer place. Obviously nerve wracking but great progress in alerts

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petterroea 2 hours ago | parent | next [-]

It sounds impressive but it's worth considering that this was a large quake that was felt by basically half of the country. You do not get this much warning if you are anywhere near where damage happens.

The 45 seconds is better thought of as the time it takes for the quake to propagate to Tokyo

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strangegecko 2 hours ago | parent | prev | next [-]

Yeah. That's leagues better than what I get in Taiwan. The alert often arrives when the building is shaking or even after. I've never had a meaningful headstart.

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sampullman an hour ago | parent | next [-]

I usually get it a few seconds ahead of time at least, in Taipei. I figured it's more related to the proximity than anything else.

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philistine an hour ago | parent | prev [-]

It would seem the forewarning depends a lot on the distance from the epicentre. This quake, for Tokyoites, was far enough from them that they could beat the earthquake's speed. I'm fairly certain the people on the East Coast near the quake got no notification ahead of the event.

	▲	wat10000 11 minutes ago \| parent [-]
		I was in a chat with people in NYC when it hit. They got advance notice, although it was just “why is everything shaking?” Followed by me going silent for a bit, so they didn’t know what was going on until it reached them.

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2 hours ago | parent | prev [-]

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