S044-01
MyShake: Lessons from the first year of public earthquake early warning delivery in California

Monday, 14 December 2020: 10:02
Virtual
Richard M Allen1, Stephen Allen2, Qingkai Kong3, Sarina Patel4, Ramon Francisco Mejia4, Sharon Pothan4, Jennifer Ann Strauss5 and Stephen Thompson4, (1)University of California Berkeley, Berkeley, CA, United States, (2)UC Berkeley Seismological Laboratory, Berkeley, CA, United States, (3)UC Berkeley, Berkeley, CA, United States, (4)University of California Berkeley, Berkeley, United States, (5)University of California, CA, United States
Recorded Presentation
Abstract:
On October 17, 2019 Governor Gavin Newson announced that the MyShake earthquake information app would now deliver ShakeAlerts across California as an element of the California Earthquake Early Warning System (CEEWS). This was the first statewide delivery of public alerts in the United States. Prior to this announcement, UC Berkeley’s MyShake app had been available globally as a citizen science project detecting earthquakes, recording ground motion waveforms, and providing earthquake information to users. But the addition of alerts to the app’s feature set significantly increased the number of users; the app—freely available in the Google Play and Apple iTunes stores—has now been downloaded by over 1 million users.

In the first year of public alert delivery, MyShake has delivered approaching 20 public alerts. Alerts are sent when ShakeAlert detects an earthquake in California with a magnitude of 4.5 or greater, and delivers the alerts to MyShake users in the region expected to experience shaking intensity of 3 or greater. The largest alert was for the June 24, 2020, M5.8 Lone Pine earthquake for which an alert was delivered to 47,747 phones. Based on alert receipts, 20% of phones received the alert within 5.1 seconds of the ShakeAlert message being created, 50% received the alert in 7.1 sec and 80% received it in 9.4 sec.

Development efforts during the year have focused on reducing alert latency and improving the user experience. A new sharded alerting system was rolled out in July 2020 which increases the user capacity of the system and reduced the latencies to one third of what they were previously based silent alert tests sent to real users. The larger (M>5) earthquakes in southern California have also provided a substantial waveform dataset and hundreds of user experience reports that we are in the process of analyzing. Finally, user feedback of the app is overall a very positive. Users are showing clear excitement and appreciation at receiving alerts tens of seconds before experiencing shaking.

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