27-5 Recent Deep Seismicity and active faulting in southern Mexico City: evidence of the presence of the Subducting Slab

Session: Evolution of Cordilleran-type orogenic systems

Presenting Author:

Ana Martin Del Pozzo

Authors:

Martin Del Pozzo, Ana Lillian¹, Quintanar Robles, Luis², Sandoval García, Mariana³, Espíndola Castro, Victor Hugo⁴, Bello Segura, Delia ⁵

(1) Departamento de Vulcanología, Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacan, Mexico City, Mexico, (2) Departamento de Sismología, Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacán, Mexico City, Mexico, (3) Posgrado en Ciencias de la Tierra, Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacán, Mexico City, Mexico, (4) Servicio Sismológico Nacional, Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacán, Mexico City, Mexico, (5) Servicio Sismológico Nacional, Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacán, CDMX, Mexico,

Abstract:

Seismicity in southern Mexico City has been difficult to monitor because there are few stations but nonetheless small magnitude transtensional events have been located in the area. Mexico City lies on Polygenetic older volcanoes (more than 1MKa) that transitioned to small monogenetic cones in the Sierra Chichinautzin.  Small magnitude (M 1-4 M)) events between 1 - 15  1 km deep and dike orientation and faulting on E-W oriented structures are consistent with north-south extension. A magnitude 3.9 event was located 119 km deep in the area (19.129 N 99.195 W) on November 19 2025 indicating slab depth in the area. This is the first time that an event is located at this depth in the Chichinautzin volcanic field showing the presence of the subducting slab below the transmexican volcanic belt. To the south (trenchward), the event was detected in several seismic stations belonging to the National Broadband Seismological Network  and to the north in the Red Sismica del Valle de Mexico but the signal shows significant variations consistent with mantle heterogeneity and  different thermal conditions. We have recently installed 3 new seismic stations in the southern part of the Volcanic field in rural Mexico City and consider that we will be able to detect more detail in the tectonics in the near future.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3, 2026

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