What controls the transition from monogenetic to polygenetic volcanism? Structural insights into the coexistence and transition between Chichinautzin Monogenetic Volcanic Field and Popocatépetl volcano, Mexico.

The transition and coexistence of large polygenetic volcanoes and monogenetic volcanic fields represents a key challenge in understanding crustal magmatism and volcanic evolution across active tectonic regions worldwide. This duality is strikingly exemplified in central Mexico. Here, the active polygenetic volcano Popocatépetl, coexists with the Chichinautzin Monogenetic Volcanic Field (CMVF), characterized by numerous small cones and lava flows reflecting short-lived, episodic eruptions. Although both volcanic styles are extensively documented individually, the fundamental tectonic and structural factors controlling their coexistence and transtition remain poorly understood. Our study aims to understand the influence of regional tectonic stress orientation and local faulting in interpreting the mechanisms that governs eruptive style transitions.

We integrated high-resolution structural mapping, remote sensing, and a 30-year seismic record (1994–2025). Fault and lineament patterns were derived from LiDAR Digital Elevation Models (DEMs) and Sentinel-1 SAR imagery, processed through slope, azimuthal, and contour analyses. These datasets were correlated with volcanotectonic (VT) earthquake records from Popocatépetl and CMVF to assess the spatial and temporal distribution of seismicity in relation to fault systems.

Our results delineate two major tectonic domains: (1) NW–SE and NE–SW fault systems characterizing the Popocatépetl volcano; and (2) a predominant E–W system defining cone alignments within the CMVF. Monogenetic cones in the CMVF align preferentially along E–W and NE–SW faults, reflecting a prevailing N–S minimum horizontal stress that facilitates direct magma ascent. In contrast, Popocatépetl is dissected by multiple, interacting, high-angle fault systems, including the active Tlamacas (NE–SW) and Nexpayantla (NW–SE) faults. The majority of pre-eruptive and co-eruptive VT earthquakes cluster along these structures, confirming their critical role in magma ascent, storage, and edifice segmentation.

We conclude that the coexistence and transition between polygenetic and monogenetic volcanism in central Mexico are fundamentally governed by the complexity and orientation of regional and local stress fields. In the CMVF, single stress regimes create efficient pathways for rapid magma ascent, favoring monogenetic activity. At Popocatépetl, intersecting and structurally complex fault systems induce magma trapping and long-term storage, driving polygenetic evolution.