UC Berkeley

MyShake is a free citizen science smartphone application that has been publicly available since 2016 and has been downloaded globally 2.6 million times. Since becoming an earthquake early warning delivery service for the US West Coast, MyShake has attracted its greatest concentration of users in the states of California, Oregon, and Washington. As a citizen science project, MyShake collects various types of data, which can be broadly categorized as long-form waveforms and real-time snippets. When a phone operating MyShake is still for 30 min, MyShake will begin monitoring the accelerometer, which is hardware built into all smartphones. A machine learning-trained pair of algorithms scan for earthquake-like motion and will record five minutes of waveform data when an earthquake is suspected to be occurring. Waveform recording can also be triggered by the delivery of an early warning message, in anticipation of imminent earthquake shaking. These data are uploaded to secure servers when phones are connected to wi-fi and power. Real-time data collected by MyShake includes state of health information sent in data snippets called heartbeats, alert receipts messages, short-term-average over long-term-average (STA/LTA) triggers whenever a monitoring phone suddenly moves, and aggregate peak acceleration values.

The data collected by MyShake represents an at-scale opportunity to explore the capabilities of a smartphone seismic network. In this work, I investigate four use-cases of smartphone data: 1) assessing how smartphones perform as early warning delivery tools; 2) using smartphone waveform data to measure ground shaking intensities; 3) incorporating real-time smartphone earthquake detections into a traditional earthquake early warning system; and 4) measuring the fundamental frequency of buildings using smartphone waveforms. The first and third objectives form a circle, generating and then delivering early warning to private citizens. We find that phones are both efficient delivery mechanisms, with warnings typically arriving on phones within 5 seconds of alert generation, and efficient earthquake detectors, with real-time triggers arriving at a backend server in the same amount of time as traditional data. Measuring acceleration and converting to shaking intensity helps evaluate the accuracy of the shaking extent produced by early warning. Using waveform data to measure fundamental frequency ventures into the realm of structural health monitoring, a critical field for earthquake preparedness and rapid response. All together, MyShake represents a novel and high-potential opportunity to make seismology accessible and applicable within communities while also supporting the creation of seismic knowledge that can be used to make the same communities safer.