The 2022 Michoacán Earthquake and Regional Seismicity

On September 19, 2022, at 18:05 local time, a magnitude 7.6 earthquake struck 35 km south-southwest of Aguililla, Mexico, at a depth of 26.9 km. This event represents the sole strong earthquake recorded in the region since 2000 according to available data.

The earthquake occurred within the tectonically active zone of Michoacán state in western Mexico. This area forms part of the Middle America Trench, where the Cocos Plate subducts beneath the North American Plate at a rate of approximately 6–7 cm per year. Subduction generates both megathrust events along the plate interface and intraslab earthquakes within the descending slab, consistent with the 26.9 km focal depth of the 2022 event.

Michoacán lies in a well-documented seismic gap segment of the subduction zone. Historical records document major earthquakes in the broader region, including events in 1911 and 1985 that produced significant ground shaking and coastal impacts. The 2022 rupture released accumulated strain along a portion of the plate boundary, producing strong shaking felt across central Mexico.

Post-event analysis indicates typical aftershock patterns for a subduction-zone earthquake of this size, though the provided data identifies no additional strong events in the immediate vicinity. The combination of depth, magnitude, and location aligns with expected behavior for intraslab or interface seismicity in this tectonic setting.

Ongoing monitoring by regional networks continues to track seismic activity, underscoring the persistent hazard posed by plate convergence in western Mexico.

References

• U.S. Geological Survey Earthquake Catalog
• Servicio Sismológico Nacional (Mexico)