Overview
- The Servicio Sismológico Nacional logged multiple shallow microsismos off Chiapas on Friday and Saturday, Sept. 4–5, with magnitudes mostly between 3.6 and 3.9 and focal depths commonly near 10 km.
- Local and federal authorities reported no damage or injuries after the Chiapas events and said life and services continued normally in nearby towns.
- One event northwest of Cintalapa was much deeper at about 145 km, a depth that made it barely perceptible at the surface according to SSN technical data.
- Separate regional monitoring recorded a tectonically unrelated sequence in Salta, Argentina, where INPRES reported a M4.7 quake at about 6 km depth followed by a M4.6 replica felt across the Valles Calchaquíes.
- UNAM, Cenapred and Protección Civil emphasize that seismicity in Mexico is year-round, that past date coincidences are chance and memory bias, and that the practical focus should be on building maintenance, drills and verified official information.