[londons_explore]

This relies on the accelerometer being always turned on - which it typically isn't when the phone screen is off.

Thats a decent amount of extra energy being used globally! And also everyone's batteries dying a little sooner.

I wonder what sample rate they have the accelerometer running at, and if it is just one axis to save power? Typically 8 bit single axis 1Hz sampling is ~10 microamps, but full 10 kHz 3 axis sampling could be 10 milliamps = 1000x more power use!

[irvymike]

All your questions/assumptions are answered in the linked paper supplementary material: 50hz, 3 axis, only when charging. Accompanied with actual sample plots for various distances from epicenter, showing p waves and s waves.

[duskwuff]

Most MEMS accelerometers have low-power modes to generate an interrupt when movement is detected. That's probably what Google is using here (and only switching to higher-power modes when there's movement).

[marcsto2]

It only runs when a phone is plugged in and stationary.