The structural architecture of the Los Humeros volcanic complex and geothermal field

The Los Humeros Volcanic Complex (LHVC) is a large silicic caldera complex in the Trans-Mexican Volcanic Belt (TMVB), hosting a geothermal field currently in exploitation by the Comisión Federal de Electricidad (CFE) ofMexico, with an installed capacity of ca. 95 MWof electric power. Understanding the structural architecture ofLHVC is important to get insights into the interplay between the volcano-tectonic setting and the characteristicsof the geothermal resources in the area. The analysis of volcanotectonic interplay in LHVC benefits fromthe availabilityof subsurface data obtained during the exploration of the geothermal reservoir that allows the achievementof a 3D structural view of the volcano system. The LHVC thus represents an important natural laboratoryfor the development of general models of volcano-tectonic interaction in calderas. In this study, we discuss astructural model of LHVC based on morphostructural and field analysis, integrated with well logs, focal mechanismsolutions and magnetotelluric imaging. The structural analysis suggests that inherited regional tectonicstructures recognized in the basement played an important role in the evolution of the magma feeding system,caldera collapses and post-caldera deformations. These inherited weak planes have been reactivated by resurgencefaults and post-caldera magma-driven hydrofractures under a local radial stress field generated by theshallow LHVC magmatic/hydrothermal system. The local stress field induced caldera resurgence andvolcanotectonic faulting. The results of this study are important to better constrain the structural architectureof large caldera complexes. Also, our study is useful to understand the structure of the Los Humeros geothermalfield and support the exploration of deeper Super-Hot Geothermal Systems (SHGSs) and engineering of EnhancedGeothermal Systems (EGSs) for electric power production in the LHVC and other active resurgentcalderas.