'Quake-detection app detected nearly 400 temblors worldwide'

A smartphone app developed by scientists has successfully detected nearly 400 earthquakes since its launch earlier this year, paving the way for a warning system that can alert users before a disaster strikes.
The MyShake app, developed at University of California, Berkeley, harnesses a smartphone's motion detectors to measure earthquake ground motion, then sends that data back to the seismological laboratory for analysis.
The eventual goal is to send early-warning alerts to users a bit farther from ground zero, giving them seconds to a minute of warning that the ground will start shaking.
That is enough time to take cover or switch off equipment that might be damaged in a quake, researchers said.

To date, nearly 220,000 people have downloaded the app, and at any one time, between 8,000 and 10,000 phones are active - turned on, lying on a horizontal surface and connected to a wi-fi network - and thus primed to respond.
An updated version of the MyShake app is available, providing an option for push notifications of recent quakes within a distance determined by the user, and the option of turning the app off until the phone is plugged in, which could extend the life of a single charge in older phones.

"The notifications will not be fast initially - not fast enough for early warning - but it puts into place the technology to deliver the alerts and we can then work toward making them faster and faster as we improve our real-time detection system within MyShake," said project leader Richard Allen, a UC Berkeley professor.

Ten months of operation clearly shows that the sensitivity of the smartphone accelerometers and the density of phones in many places are sufficient to provide data quickly enough for early warning, researchers said.
The phones readily detect the first seismic waves to arrive - the less destructive P waves - and send the information to Berkeley in time to issue an alert that the stronger S wave will soon arrive.
"We already have the algorithm to detect the earthquakes running on our server, but we have to make sure it is accurate and stable before we can start issuing warnings, which we hope to do in the near future," Kong said.

The app can detect quakes as small as magnitude 2.5, with the best sensitivity in areas with a greater density of phones.
The largest quake detected occurred on April 16 in Ecuador: a 7.8 magnitude quake that triggered two phones, 170 and 200 kilometers from the epicenter.
Researchers believe the app's performance shows it can complement traditional seismic networks, such as that operated nationally by the US Geological Survey, but can also serve as a stand-alone system in places with few seismic stations, helping to reduce injuries and damage from earthquakes.
The research was published in the journal Geophysical Research Letters.