July 17, 2026 Earthquake: Chiapas, Guatemala, Mexico

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Tectonic Summary

The July 17, 2026, M 7.3 earthquake occurred offshore southern Mexico at a shallow depth of about 20 km. This earthquake occurred in an active subduction zone where the Cocos plate subducts northeastward beneath Mexico and Central America at the Middle America Trench. Based on the focal mechanism, this event occurred as a result of reverse (thrust) faulting, likely on the main subduction thrust. At the location of this event, the Cocos plate converges with North America at a rate of approximately 76 mm/yr, in a northeast direction.

While commonly plotted as points on maps, earthquakes of this size are more appropriately described as slip over a larger fault area. Reverse faulting events of the size of the July 17, 2026, earthquake are typically about 60 km x 30 km in size (length x width).

Two small foreshocks preceded the July 17 earthquake, including a M 4.1 on July 14 and a M 4.7 88 minutes prior to the mainshock. There is a well-documented history of moderate to large earthquakes along this plate boundary. Since 1950, 50 previous earthquakes of magnitude 7 or larger have occurred in Central America on or near the active plate boundary interface. Seven earthquakes of magnitude 7 or larger have occurred within 155 miles (250 km) of today’s earthquake since 1950. This earthquake is located in a similar rupture region to earthquakes of M 7.3 in 1970 and M 7.2 in 1993, and it is located at the southern extent of an M 8.2 earthquake that occurred in 2017. The 2017 earthquake resulted in around 20 fatalities and generated a destructive regional tsunami. Shaking in the 1993 M 7.2 earthquake caused one fatality and considerable damage in Guatemala. Magnitude 7 and larger earthquakes in Mexico and Guatemala have led to varying societal impacts, with the impacts largely dependent on the proximity of these earthquakes to major population centers.

Reference #14441, #14442:

Mexico damages: Almost 400 homes (22 uninhabitable, 1 collapses) 3 hospitals damages, 2 medical centers, 25 schools. 17 municipalities in state of Chiapas were affected by infrastructure damage: Cacahoatan, Suchiate, Tapachula, Chiapa de Corzo, Tecpatan, Villaflores, Montecristo de Guerrero, Huixtla, Bella Vista, Chicomuselo, Frontera Comalapa, Capitan Luis Angel Vidal, Acala, Frontera Hidalgo, Jitotol, Ostuacan, and Motozintla.

Guatemala damages: 3 homes minor damage, 10 moderate damage, and 3 severe damage. The departments with the most emergencies are San Marcos, Quetzaltenango, Huehuetenango, Quiché, Sololá, Suchitepequez, Sacatepequez, and Guatemala.