California has earthquake early warning. Most Californians don’t have it set up. Of those who do, most haven’t thought through what they’d actually do with the warning.
The Physics Behind the Warning
ShakeAlert detects fast-moving P-waves at seismic sensors near the epicenter and transmits an alert before the destructive S-waves arrive at your location. Close to the epicenter: 0–5 seconds. 20 miles out: 5–10 seconds. 50+ miles: 15–30+ seconds. That’s not much. But it’s enough.
How to Get the Warning
Wireless Emergency Alerts: iPhone: Settings > Notifications > Government Alerts > Emergency Alerts (ON). Android: Settings > Safety & Emergency > Wireless Emergency Alerts (ON).
MyShake App: USGS’s official app (free, iOS and Android). Provides earthquake alerts and a log of recent quakes.
What to Do With the Warning
Drop: Get low. Reduce your height to reduce injury from falling objects.
Cover: Get under a sturdy desk or table. If not available, get against an interior wall and protect your head. The “doorframe” thing is a myth.
Hold On: If under a table, hold onto it. Tables move during shaking.
The 30 Seconds After
- Don’t move immediately — aftershocks can follow within seconds
- Check yourself for injury. Adrenaline masks pain.
- Check for gas smell — if you smell gas, get out. Don’t use electrical switches.
- Don’t use elevators
- Text, don’t call — networks saturate. Use your out-of-state contact.
- Turn on your battery-powered NOAA radio
What This System Doesn’t Fix
The most important earthquake prep most California households haven’t done: securing furniture and heavy objects. Bookcases, water heaters, refrigerators, TVs — these cause the majority of non-structural earthquake injuries. L-brackets, furniture straps, and water heater straps are cheap and straightforward.
Second most overlooked: knowing how to shut off your gas. Find your meter, know where the shutoff is, keep a wrench accessible nearby — not inside the house.
Set up alerts on every phone in your household today. Then walk through your home looking at what’s unsecured at height. Then practice Drop, Cover, Hold On once — actually get on the floor and do it.
Early warning gives you seconds. Preparation gives you the ability to use them.
