Overview

• The National Seismological Service reported a magnitude‑4.4 quake at 05:44 on Sept. 14, located 106 km southwest of Los Mochis, Sinaloa, at a depth of 10 km.
• A preliminary magnitude‑4.5 earthquake struck near Mapastepec–Pijijiapan, Chiapas, on the evening of Sept. 13; Protección Civil initiated review protocols and reported no damage or injuries.
• SASMEX did not trigger Mexico City alerts because the events fell below distance–magnitude criteria, which generally require around M6 for sources beyond 350 km and about M5 for closer events.
• SSN logged 34 tremors early Sept. 13, with the strongest at M3.9 in Oaxaca and M3.8 in Chiapas, consistent with Mexico’s high baseline seismicity.
• The Second Simulacro Nacional is scheduled for Friday, Sept. 19 at 12:00 (CT), featuring for the first time a wireless Cell Broadcast alert to millions of phones marked “SIMULACRO,” alongside sirens in covered states.