[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.