Guerrero, Mexico experiences earthquake swarm and coastal swell warning

On June 30, 2026 the Mexican National Seismological Service recorded more than a dozen tremors along the Pacific coast, the strongest reaching magnitude 3.9 near Frontera Comalapa, Chiapas. The state of Guerrero saw the highest activity, with several quakes of magnitude 3.5‑3.7 near San Marcos, Acapulco, Petatlán and Zihuatanejo; no injuries or damage were reported.

The next day, July 1, another swarm of eight tremors struck the Costa Chica of Guerrero, all centred near San Marcos. Magnitudes ranged from 2.0 to 3.6 and depths were shallow. Authorities noted the events are typical of a seismic “swarm” and have not confirmed any connection to the Guerrero seismic gap, a long‑quiet segment of the fault.

Separately, Guerrero’s civil‑protection agency issued a preventive alert for a “Mar de Fondo” event expected to produce waves of 1.5‑2.1 m and strong return currents along the state’s coastline for up to 72 hours. The advisory covers coastal municipalities from Acapulco to Zihuatanejo, urging residents to avoid water activities, reinforcing lifeguard presence, and directing hotels, restaurants and small‑boat operators to adopt safety measures.