Last time we had a reasonably powerful one in Portugal, I grabbed my phone the house was still shaking and it already had the Android warning!

I was surprised as I didn't even know it was a thing.

I was also a bit spooked as it was in the ocean, near the coast, and when I turned on my FM radio as we were always taught in school, all I heard were pre-recorded music programs.

Turns out it didn't meet the threshold for a warning so the authorities didn't issue any message about tsunami danger. I think they should've anyway, as I wasn't the only one that had that thought.