[Galanwe]

I don't get it. I thought earthquake alerts were meant to trigger _before_ the earthquake arrives. If it happens 30 secondes after detecting vibrations, not considering the false positive, it can only mean "hey, you just felt, or are feeling an earthquake, hope you're sheltered".

[foobarbecue]

Earthquake early warning only works because the internet is faster than seismic waves. It only works for people who are far enough from the epicenter.

[mangateparu]

This is how I experienced the Google Earth Alerts in Wellington, NZ which experiences frequent earthquakes. Earthquake happens. 30 seconds to five minutes later I get an alert from Google.

The best earthquake indicator is an old house with wooden windows that you'll hear rattling five seconds before you get to feel it.

[foobarbecue]

Here in San Clemente, CA the one alert I've had (earlier this year) actually gave me about 10 seconds warning for some pretty strong shaking!

[neurostimulant]

A faster moving small quake (p-wave) will precede the bigger, more damaging quake. This system detects the p-wave and alert people hoping they can get out in time before the big quake hit.

[foobarbecue]

To clarify: pressure waves travel faster than shear waves. Both start at the same time and the same place (epicenter).

Earthquake early warning only works because the internet is faster than seismic waves. It only works for people who are far enough from the epicenter.

[guluarte]

This is when the earthquake is a few hundred kilometers away, such as in Mexico City, where most earthquakes occur off the coast and the waves take a few minutes to reach the city.

[tgv]

The first alert made the phones vibrate (or people touching them), which got falsely detected as an earthquake.

[ragebol]

Yes, and they sent a notification apparently after the detection. That is not a warning system

[foobarbecue]

Earthquake early warning only works because the internet is faster than seismic waves. It only works for people who are far enough from the epicenter.