The Magma plumbing system and seismo-tectonics of the Guatemala-Mexico triple junction as revealed by the seismicity of the Tacaná volcano before and after the 2017 Mw8.2 Chiapas earthquake
Por:
Legrand, D, Perton, M, Spica, Z, Jon, J, Alatorre-Ibargüengoitia, M, Peiffer, L, Campion, R, Valdés, C, Caballero-Jiménez, G, Vargas-Zamudio, K, Espíndola, JM, De la Cruz-Reyna, S
Publicada:
1 jul 2025
Resumen:
The triple junction between the North American, Caribbean and Cocos plates at the Guatemala-Mexico border is not well understood. It forms a broad region from around the active Tacan & aacute; volcano up to the Guatemala City graben. Tacan & aacute; is the westernmost active volcano of the Central American volcanic arc and is located at the intersection of four major active faults: the Polochic, Motagua, Jalpatagua and Tonal & aacute; faults. Using seismicity around the Tacan & aacute; volcano, we show that there is moderate to low tectonic seismic activity between the Guatemala City graben and the Tacan & aacute; volcano, possibly related to the ancient extremes of the Motagua and Jalpatagua faults. Therefore, we speculate that the triple junction would be located onshore, around the Tacan & aacute; volcano.We located earthquakes around the Tacan & aacute; volcano between January 2017 and October 2018, a period that includes the large Mw8.2 Tehuantepec (Chiapas) earthquake of 2017 September 8, located similar to 190 km away. We identified four distinct types of seismicity, interpreted as having tectonic, hydrothermal, intermediate depth magmatic and deep magmatic origins. The tectonic seismicity occurred at depths between similar to 5 and similar to 30 km b.s.l., and may be associated with three faults around the Tacan & aacute; volcanic complex. These faults are oriented in NE-SW, aligned with the four Tacan & aacute; volcanic edifices; NW-SE, consistent with the Jalpatagua fault; and approximately EW, corresponding to the Motagua fault. The hydrothermal seismicity is observed at shallow depths, from the subsurface to about 2 km b.s.l., predominantly in the western sector of the Tacan & aacute; summit, and partially beneath the San Antonio volcano, an area known for intense hydrothermal activity. This seismicity is spatially related to the shallow portions of the same three faults described above. The intermediate depth magmatic seismicity is detected at depths between 5 and 12 km b.s.l. and is interpreted to be related to the presence of a shallow magma chamber beneath the Tacan & aacute; volcanic complex. Finally, the deep magmatic seismicity is located in the eastern part of the Tacan & aacute;, at depths ranging from 15 km to about 22 km b.s.l. This seismicity is interpreted to be due to a vertical dike intrusion that connects a deep magma reservoir located between 30 and 40 km depth, to the hypothesized shallower magma chamber associated with the intermediate depth seismicity.
Filiaciones:
Univ Nacl Autonoma Mexico, Inst Geofis, Ave Univ 3000, Ciudad De Mexico 04510, Mexico
Univ Nacl Autonoma Mexico, Inst Ingn, Ave Univ 3000, Ciudad De Mexico 04510, Mexico
Univ Michigan, Ann Arbor, MI 48109 USA
Univ Ciencias & Artes Chiapas, Inst Invest Gest Riesgo & Cambio Climat, Libramiento Norte poniente 1150, Tuxtla Gutierrez 29039, Chiapas, Mexico
Ctr Invest Cient & Educ Super Ensenada CICESE, Ensenada 22860, Baja Ca, Mexico
Ctr Invest Cient & Educ Super Ensenada CICESE, La Paz 23080, Baja Ca Sur, Mexico
Ctr Nacl Prevenc Desastres CENAPRED, Ave Delfin Madrigal 665, Ciudad De Mexico 04360, Mexico
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