According to the Servicio Sismológico Nacional (SSN), a 4.3 magnitude earthquake struck on Tuesday with an epicenter located 135 kilometers southwest of Ciudad Hidalgo in the state of Chiapas. The official report from the agency states that the movement occurred at 13:29:03 hours, registering at coordinates latitude 14.14 and longitude -93.28 with a depth of 18 kilometers.
This seismic activity forms part of a broader monitoring effort across Mexico, where the SSN has tracked thousands of aftershocks following a major 7.4 magnitude earthquake that hit Ciudad Hidalgo on July 17. According to official data released via the agency’s X account, @SismologicoMX, a total of 2,214 aftershocks were recorded up to 08:00 hours on September 1, with the largest aftershock reaching 6.5 magnitude.
Daily Seismicity Report and Regional Distribution
Between midnight and 4:43 in the morning on September 1, the SSN registered 33 separate sisms. None of these events surpassed a 4.0 magnitude, and they concentrated primarily across five states: Chiapas, Oaxaca, Guerrero, Colima, and Baja California Sur.
Chiapas recorded the highest activity with 13 tremors ranging between magnitudes 3.2 and 3.9, mostly occurring southwest of Arriaga, Ciudad Hidalgo, and Mapastepec. Oaxaca followed with 8 tremors between 2.8 and 3.8 magnitude near Salina Cruz, Río Grande, Pinotepa Nacional, and Matías Romero. Guerrero registered 7 sisms ranging from 2.2 to 3.5 near San Marcos and Petatlán, while Colima logged 3 tremors between 3.2 and 3.3 near Manzanillo and Villa de Álvarez. Baja California Sur recorded 2 events, including a 2.2 magnitude tremor near San José del Cabo and a 3.9 magnitude event north of Santa Rosalía in the Gulf of California.
Tectonic Plate Interactions Along the Pacific Coast
The vast variation in depth—ranging from 5.0 kilometers in Manzanillo, Colima, to 140.8 kilometers in Cintalapa, Chiapas—highlights complex underground mechanics. According to the SSN, earthquakes deeper than 90 kilometers all occur in Chiapas due to the internal activity of the Cocos plate as it sinks beneath Mexican territory. The Pacific coast from Colima to Chiapas sits directly above the boundary between the Cocos and North American plates, where continuous sliding generates daily small and moderate sisms.
External reporting from elcomercio.pe notes that this seismic monitoring is operated in conjunction with the Universidad Nacional Autónoma de México (UNAM). The publication emphasizes that the ongoing subduction of the Cocos plate under the North American plate drives a constant release of energy along the Pacific coast, providing essential data for academic analysis, risk map updates, and civil protection protocols.
Did You Know? Mexico’s high seismic activity is driven by the interaction of five distinct tectonic plates underlying the national territory: the Cocos, Norteamérica, Pacífico, Rivera, and Caribe plates.
Expert Insight: Continuous tracking of low-magnitude background seismicity allows researchers and civil protection authorities to differentiate between everyday micro-quakes and significant structural shifts, thereby reducing misinformation and strengthening regional emergency preparedness.
Frequently Asked Questions
What data points are included in each line of the SSN seismicity report?
Each entry contains four specific data points: magnitude on the Richter scale, exact date and time in central Mexico time, geographic location and distance from a reference town along with latitude and longitude coordinates, and depth in kilometers.
How do experts explain the deepest earthquakes recorded in the region?
Tremors occurring at depths greater than 90 kilometers are attributed to the internal activity of the Cocos plate as it descends beneath Mexican territory in the state of Chiapas.
Were any of the sisms recorded on September 1 perceived widely by the public?
According to the SSN, none of the 33 sisms registered between midnight and early morning surpassed magnitude 4.0, placing them in the category of lightly sensed or unperceived by the general population except near the immediate epicenters.
How do local preparedness plans in your region account for frequent seismic activity?