Peter Griffin, Contributor. 29 April 2021, 9:46 am
Tens of thousands of Kiwis regularly reach for their phone when they feel the shudder or rocking that suggests there’s been an earthquake.
We head straight for the GeoNet app, which, almost instantly, displays a quake’s magnitude, depth and location.The information is generated by a network of seismic sensors the length of the country that GNS Science maintains to monitor earthquake activity and even allows app users to report whether they felt the quake.
This much-beloved app helps define our relationship with the ever-shifting geology of our country. But it is literally an after-though, giving us context on what we’ve just felt. What if we could get an alert to tell us the earthquake is coming?
Google is attempting to do that using smartphones as a distributed network of sensors to detect earthquakes and warn users so they have time to find a safe spot to ride out the shaking. Google today introduced its Android Earthquake Alerts System to New Zealand and Greece after launching it last August in partnership with the United States Geological Survey (USGS).
The system is based on the accelerometer in Android phones that, among other things, senses the position of the device, adjusting the screen orientation to suit and enables pedometers and health tracking apps by sensing the motion of the phone.
“If the phone detects shaking that it thinks may be an earthquake, it sends a signal to our earthquake detection server, along with a coarse location of where the shaking occurred,” Boone Spooner, Google Product Manager, Android, explained in a company blog post.
“The server then takes this information from many phones to figure out if an earthquake is happening, where it is and what its magnitude is.”
If you have an Android phone, the system is switched on by default. It means that in future, if there’s a decent shake in your area, which Google knows can detect due to GPS and cell site data, it will send you an alert on your phone advising you to take cover.
Google’s earthquake early warning alerting
Alerts will be sent for quakes of magnitude 4.5 or greater.
The detection system is based on ShakeAlert, an early-warning system that has been operational based on 700 seismometers on the West Coast of the US over the last couple of years and which will expand to Washington in May.
According to ShakeAlert, studies in Washington, Oregon and California show the warning time the detection system can provide range from “seconds to tens of seconds”.
“ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake,” ShakeAlert claims.
Only a handful of countries have established earthquake early warning networks. Japan in particular has led the way with an Early Warning System run by the Japan Meteorological Agency. Japanese residents regularly get blaring alerts on their smartphones and via radio and TV broadcasts to signal that an earthquake is on the way.
Google’s system has the blessing of GNS Science, which sees it as complementary to GeoNet and the Civil Defence alerts that are sent to smartphones. Android users need to be running Android OS 5.0 (Lollipop) which came out in 2014, so should see the majority of Android phones still active able to support it.