eismology experts consulted by Google said turning smartphones into mini-seismographs marked a major advancement, despite the inevitably of erroneous alerts from a work in progress, and the reliance on a private company’s algorithms for public safety. More than 2.5 billion devices, including some tablets, run Google’s Android operating system.

“We are on a path to delivering earthquake alerts wherever there are smartphones,” said Richard Allen, director of University of California Berkeley’s seismological lab and visiting faculty at Google over the last year.