This is great. But, why dont they start with Air Quality first? I think, AQ is something, I ll check more often and helpful in decision making than get earthquake alerts.
The average phone doesn't have an air quality sensor. The average phone does have a seismometer in the form of a accelerometer.
For fixed locations, there are cheap P-wave detection earthquake alarms based on mechanical pendulums that will give seconds of warning.
Hope the default settings are better than the MyShake app for iOS, which IIRC helpfully defaulted to notifying one of all quakes near 0 latitude, 0 longitude. It would be nice to
have a settable low threshold so one could become familiar
with the notifications at 2.5..3.5 Richter, and then set
to a higher threshold.
Made me think of [that artist who spoofed a traffic-jam in google maps](http://simonweckert.com/googlemapshacks.html). I wonder how many devices it would take to spoof an earthquake, hopefully this is designed better.