Earthquake Preparedness in Mexico City: Alerts, Drills and Kits
The city has a public earthquake alarm, regular drills and street loudspeakers. How the warning works, what to do in the seconds you get and how to prepare your home.
Mexico City has a public earthquake alarm, the Mexican Seismic Alert System (SASMEX), which sounds through street loudspeakers, radio and TV when sensors detect a strong quake far away. It gives roughly 20 to 120 seconds of warning, depending on distance; a quake on the Michoacán coast would give the capital more than 100 seconds.
How does the seismic alert work?
SASMEX is run by the Center for Seismic Instrumentation and Registry (CIRES), a nonprofit, and is recognized by federal and city authorities as the country’s official earthquake warning. Since 2012 it has used 96 seismic sensors along the Pacific subduction zone in Jalisco, Colima, Michoacán, Guerrero, Oaxaca and Puebla, according to CIRES’s description of the system.
When at least two stations detect strong shaking, the system estimates the magnitude in seconds and decides, city by city, whether to warn. For Mexico City, an alert goes out in the cases CIRES lists, as of November 2026:
- An estimated magnitude above 5 within 200 kilometers.
- Above 5.5 within 350 kilometers.
- Above 6 farther than 350 kilometers.
Quakes outside the sensor network, very far away or below those thresholds do not trigger the public alarm. A quake that starts close to the city may give little or no warning, so the alarm is a help, not a guarantee.
How will you hear the alert?
The official alert sound lasts one minute in Mexico City and is used only for real alerts and authorized drills; misusing it is an offense under city law. CIRES lists these ways the alert reaches people:
- Street loudspeakers run by the city’s C5 command and monitoring center, used for the alert since September 19, 2015.
- Most open radio and TV stations in the capital.
- The Metro system, the first user of the alert.
- Dedicated receivers in many schools and government buildings.
CIRES warns that alerts sent through social networks or internet-based apps can arrive late. It favors cell broadcast, which pushes the alarm to every phone connected to an antenna in the region without an app. Do not rely on a phone app alone; know where the nearest loudspeaker is and keep a radio at home.
What should you do when the alert sounds?
Act on the alarm immediately; the warning time is short and you will not get a second signal. Practice these steps with everyone at home:
- Stay calm and stop what you are doing. Turn off the stove if it is right next to you.
- If you are on the ground floor or a low floor and the exit is close and clear, walk out to an open area away from walls, glass and power lines. Do not run and do not use elevators.
- If you cannot get out in time, go to the safe spot you chose in advance: away from windows, mirrors, shelves and hanging lamps, next to a structural column or interior wall.
- Drop, cover your head and neck, and hold on until the shaking stops.
- Stay out of stairwells while the building is moving.
In a car, pull over away from bridges, overpasses and buildings and stay inside. On the Metro, follow staff instructions and announcements.
What should you do after a strong quake?
- Check yourself and others for injuries. Call 911 for anyone hurt or trapped.
- Smell for gas. If you notice it, close the gas valve at the tank or meter, open windows, do not use switches or flames, and leave.
- Leave by the stairs if you see cracks in columns or beams, stairs pulling away, or doors jammed by a twisted frame, and do not go back in until the building is inspected.
- Expect aftershocks, and keep away from damaged facades and balconies on the street.
- Send short text messages instead of calls so the network stays free for emergencies.
- Follow official channels, such as the city government and civil protection accounts, for instructions and shelter locations.
Our list of emergency numbers in Mexico City includes Locatel, the city’s service line, and the CFE number for power cuts.
What goes in an earthquake go-bag?
Keep a backpack (mochila de emergencia) by the door with supplies for the first 72 hours:
| Item | Why it helps |
|---|---|
| Water and non-perishable food | Water service can fail after strong quakes |
| Flashlight and battery radio, spare batteries | Power cuts; official updates without internet |
| Copies of passport, resident card and insurance policy | Proving identity and coverage if the originals are stuck inside |
| Medicines for a week and prescriptions | Pharmacies may close or run short |
| First aid kit, whistle, face masks | Minor injuries, signaling for help, dust |
| Cash in small bills, phone charger and power bank | Card terminals and ATMs may be down |
| Sturdy shoes and a warm layer | Broken glass outside; nights spent outdoors |
Agree on a meeting point near home and a contact outside the city whom everyone in the family calls. If you rent, check the building’s evacuation route and ask whether it has a civil protection plan; our guide to renting an apartment in Mexico City lists other questions for the landlord.
How do national earthquake drills work?
The federal and city governments hold national drills (Simulacro Nacional), announced in advance, during which the real alert sound plays on loudspeakers and broadcast media. Recent drills have also been used to test alerts sent to mobile phones. Treat a drill as practice: walk your route, time how long it takes to reach the street and fix what slows you down. Schools, offices and many residential buildings take part.
How do you know if your building is safe?
Buildings on the old lake bed shake more, and the city’s building rules set stricter design requirements there. Our guide to the Mexico City Risk Atlas shows how to check an address for ground cracks, the 2017 damage map and the seismic zone. After a strong quake, a structural engineer has to check any building with visible damage; do not rely on the landlord’s word.
Bottom line
Pick your safe spot and exit route today, pack the go-bag and walk the route once with everyone at home. When you hear the alarm, move at once: those seconds are the whole point of the system.
FAQ
How much warning does the Mexico City earthquake alarm give?
CIRES says SASMEX gives roughly 20 to 120 seconds, depending on how far the quake is from the city. A quake on the Michoacán coast would give Mexico City more than 100 seconds.
Why didn’t the alarm sound during a quake I felt?
The alarm sounds only when the estimated magnitude and distance meet its thresholds. Quakes that start outside the sensor network, near the city or below those levels can be felt without an alert.
Can I get the earthquake alert on my phone?
Phone alerts have been tested during national drills, and many unofficial apps exist. CIRES warns that internet apps can be delayed, so treat the loudspeakers, radio and TV as the primary warning.
Should I run outside when the alert sounds?
Only if you are on a low floor with a short, clear exit. On higher floors, go to your safe spot, drop, cover and hold on, and use the stairs once the shaking stops.
