For decades, every Tuesday at noon, San Francisco residents heard a siren followed by a public safety message via a network of loudspeakers. In a city that was forged in a crucible of earthquakes and fire, the 15-second message was a reminder to prepare for the worst — even if many residents ignored it.

In December 2019, the city's Department of Emergency Management announced that it was taking the system offline for two years to improve reliability and security in an overhaul that could cost as much as $2.5 million. Now that the tradition has been interrupted, has the rhythm of city life lost a step? Also, who's likely to hear the Tuesday noon siren and what does it say about class and privilege?

And finally, what's in your earthquake kit?