irvymike (u/irvymike)

irvymike commented on Android Earthquake Alerts: A global system for early warning research.google/blog/andr... · Posted by u/michaefe

Miraste · 5 months ago

That would be quite an implementation flaw if it didn't account for the phone's own vibrations. Lots of countries use widespread emergency alert messages frequently.

irvymike · 5 months ago

They fixed this bug, we had plenty of emergency cell broadcasts since the false alarm.

irvymike commented on Android Earthquake Alerts: A global system for early warning research.google/blog/andr... · Posted by u/michaefe

londons_explore · 5 months ago

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 · 5 months ago

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.

irvymike commented on Android Earthquake Alerts: A global system for early warning research.google/blog/andr... · Posted by u/michaefe

irvymike · 5 months ago

Recently they had a significant country wide false alarm in Israel at 3AM... There was a emergency alert cell broadcast (similar to amber alert), which caused everyone to move their phone at the same time, which was falsely detected as an earthquake, which caused an Android earthquake alert to be sent to all phones in Israel 30 seconds later. I guess they didn't plan for this scenario

Edit: Arstechina article seems to mention this: "only three were false positives. One of those was triggered by a different system sending an alert that vibrated a lot of phones"