"Earthquake Early Warning now available publicly in California"

Details here: MyShake including explanatory videos.

U.C. Berkeley Seismology Lab

According to the website, currently available only for ios devices.

There's a link to "Get it on Google Play" up now:

https://play.google.com/store/apps/details?id=edu.berkeley.bsl.myshake

Requires Android 4.4 and up

I have a similar app on my phone - but it does earth wide volcanoes and earthquakes. I still a bit dubious about early warnings for earthquakes because the science is so young but it is very interesting to know when tremors are hitting a region and to prepare for a higher magnitude quake.

In my part of the world, we have just about the lowest frequency and magnitudes on the planet (Canadian prairies). Our buildings don't even have any earthquake shake in their designs as a result. But its fun to watch the rest of the world vibrate and have active earth movements.

Since this is one of the first implementations of this system, those in the know predict that there will be growing pains, stumbles, and errors as proficiency is attained.

Since the system depends upon the different speed between the progress of the EQ wave front and the much faster electronic transmission of the knowledge of the event, those at the epicenter will get no warning at all while those at a greater distance will learn either a few seconds to several minutes before the EQ arrives.

Even just a few seconds advance warning is better than no warning at all. All the EQs I have experienced have been pretty mild, but even so, warning would be useful.