[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!