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Complex plumbing and conduit control on the eruptions of the last 30 years at Popocatepetl Mexico revealed by multiparameter monitoring

Ana Lillian Martin Del Pozzo 1, Gerardo Cifuentes1, Sandra González1, Alicia Martines-Bringas2 and Carlos Mendoza3

  • Affiliations:  1Instituto de Geofísica, UNAM, Ciudad Universitaria, Ciudad de México, México. 04510; 2Centro de Prevención de Desastres, Ciudad de México, México; 3Facultad de Ingeniería, Ciudad Universitaria, Ciudad de México, México. 04510 

  • Presentation type: Talk

  • Presentation time: Monday 09:15 - 09:30, Room R280

  • Programme No: 1.2.4

  • Theme 1 > Session 2

Abstract

Popocatepetl volcano that is 37 mi from Mexico City and stands 5452m asl, started erupting in 1994 and since then has had varying magma compositions and mineral assemblages that change within days. From 1996 until 2019, over 85 successive domes were formed and destroyed in the crater producing mostly glassy ash particles. Vesicular clasts contain 2-7 MgO wt% and 56-66 SiO2 wt%. Different magma batches ascend from the base of the crust to shallow depths and mix with different magma bodies in short episodes. Pyroxene geobarometry indicates that magma rises from depths of 7, 13, 25, 30, 35 and 43 km. Larger explosive events in 1997, 2001, 2013, 2019 and 2023 were associated with influx of deeper more gas-rich magma days before. Negative magnetic anomalies, increases in harmonic tremor, and B and PCO2 in the spring water preceded the larger more mafic events and allowed us to advice Civil Protection weeks before. Shallow stagnation in the conduit caused small plugs to form since 2019 until new magma batches with changing compositions pushed them out. The first domes contained abundant forsteric olivene that was replaced as a mafic end-member by Mg-rich orthopyroxene after the first years but the evolved hybrids continued to vary in the larger events. Seismic activity is concentrated down to 11km under the crater and to the southeast of the crater We consider that the plumbing system is probably made up of a series of sills and dikes.