San Francisco

Exactly: i was reading more details provided by the USGS and the alert system, and apparently magnitude 5 is the current cutoff. They are exploring options such as including location or timing guesses in the alerts and they're taking input on this.

Edit: if you follow this USGS link and fill out a brief anonymous report about where you were and whether you felt anything, toward the end there's a place you can click to open optional additional questions about how the alert reached you, whether you found the alert helpful, and what ways you might like to see future earthquake alerts improved or contain more information. Also whether you feel they should be sent for a lower or higher minimum magnitude threshold.

https://earthquake.usgs.gov/earthquakes/eventpage/nc73948665/tellus