Mobile app captures nearly 400 earthquakes worldwide

An application, or app, developed by researchers at the University of California, Berkeley, has recorded nearly 400 earthquakes since it was launched in February this year.

The app, called MyShake, runs in the background on smartphones with the Android operating system, harnesses a device's motion detectors to measure ground motion, and then sends that data back to the Berkeley Seismological Laboratory for analysis.

Designed to build a worldwide network of smartphone earthquake detectors, the eventual goal of the researchers 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 and prompting them to take cover or switch off equipment.

The app can detect quakes as small as magnitude 2.5, with the best sensitivity in areas with a greater density of phones.

As of this week, when an updated version of the MyShake is available for download, nearly 220,000 people have downloaded the app, and at any one time, between 8,000 and 10,000 phones are active, namely turned on, lying on a horizontal surface and connected to a wi-fi network, and thus primed to respond.

The largest number of phones to record a quake was 103, after the 5.2 magnitude quake that occurred on the San Jacinto fault near Borrego Springs in San Diego County, California, on June 10. Phones 200 kilometers from the epicenter detected that temblor. 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.

The updated app provides an option for push notifications of recent quakes within a distance determined by the user. "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 of earth and planetary sciences and director of the seismology lab.

The researchers believe that 10 months of operation 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.

"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," said UC Berkeley graduate student Qingkai Kong, who developed the algorithm at the heart of the MyShake.

At the time of its initial release in February, the researchers argued that a crowdsourced seismic network might be the only option for many earthquake-prone developing countries, such as Nepal or Peru, that have a sparse or no ground-based seismic network or early warning system, but do have millions of smartphone users. Endit