Safety — Earthquakes & Tsunamis
Prepared, not scared. What you need to know before you arrive.
Earthquakes in Acapulco
Guerrero is one of Mexico's most seismically active states (~25% of the country's seismicity), due to the subduction (sinking) of the Cocos tectonic plate beneath the North American plate. Tremors are felt occasionally; most are minor. Modern buildings are constructed to withstand them.
The Guerrero Seismic Gap
A seismic gap is a fault segment where no major earthquake has occurred in a long time, so it "accumulates" energy. The Guerrero Gap runs roughly from Acapulco to Papanoa; its last major rupture was in 1911 (~M7.5). It is one of the most closely monitored gaps in the Americas.
The SATREPS project (2016–2022) joined UNAM with the University of Kyoto, Japan and the JICA agency, deploying seafloor instruments off Guerrero. In 2025 they published in Science Advances the first worldwide evidence of signals that precede large earthquakes. The honest conclusion: earthquakes still cannot be predicted.
Table 4 — Key historical earthquakes
| Year | Event | Magnitude | Location | Relevance |
|---|---|---|---|---|
| 1787 | San Sixto earthquake & tsunami | ~M8.6 | Guerrero-Oaxaca coast | Largest recorded in Mexico; ~4 m tsunami in Acapulco |
| 1911 | Last major Gap rupture | ~M7.5 | Guerrero Gap | The Gap has been "loading" energy since |
| 1957 | "Ángel" earthquake | M7.7 | ~90 km SE of Acapulco | Damage in Guerrero and Mexico City |
| 1985 | Michoacán earthquake | M8.1 | Michoacán coast | Catastrophe in CDMX; defined Gap research |
| 2012 | Ometepec earthquake | M7.5 | Guerrero-Oaxaca | Record aftershock sequence in Mexico |
| 2014 | Papanoa/Petatlán earthquake | M7.2 | Northern Gap | Damage in Guerrero and Mexico City |
| 2021 | Acapulco earthquake | M7.0–7.1 | ~11 km from Acapulco | Local tsunami of 0.37–0.48 m within ~5 min |
| 2026 | San Marcos earthquake | M6.5 | San Marcos, Guerrero | Felt across a large part of Mexico (Jan 2, 2026) |
Sources: SSN/UNAM, peer-reviewed journals, Wikipedia.
Tsunamis
Rare but possible after a large submarine earthquake. The largest documented was the 1787 San Sixto earthquake: ~4 m waves in Acapulco that overtopped the dock, repeating for 24 hours. The 2021 Acapulco earthquake generated a small local tsunami of ~0.4 m, just 5 minutes after the quake.
The Coyuca sandbar is a low strip of land between the ocean and the lagoon, making it more exposed to flooding than elevated terrain.
⚡ Guest protocol
Golden rule: if you feel a strong, prolonged earthquake while at the beach, do not wait for any alarm — move away from the ocean and get to high ground immediately.
- During the earthquake: protect yourself (drop, cover, hold on), stay away from windows and falling objects.
- Once it stops: if you are at the beach and the quake was strong and prolonged, or if you see the ocean receding abnormally, evacuate to high ground immediately, on foot.
- Do not return until authorities give the all-clear: multiple waves can follow.
Official alert system
The Mexican Navy (SEMAR) operates the Tsunami Alert Center (CAT). After a large submarine earthquake, the CAT evaluates and broadcasts alerts via radio, TV, social media, and local authorities.