Fracking in Oklahoma cause of most earthquakes
One of the most active areas of the world are the fracking fields of Oklahoma.
The Android app harnesses a smartphone's motion detectors to measure earthquake ground motion, then sends that data back to the Berkeley 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's enough time to take cover or switch off equipment that might be damaged in a quake.
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 will be available for download Dec. 14 from the Google Play Store, 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 of earth and planetary sciences and director of the seismology lab.
In a presentation on Wednesday, Dec. 14, during this week's annual meeting of the American Geophysical Union in San Francisco, UC Berkeley developer and graduate student Qingkai Kong will summarize the app's performance.
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.
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 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 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. ■