Thermo-Mechanical Modeling of Deformation Processes Driving Seismicity at Campi Flegrei Caldera

Over the past two decades, Campi Flegrei caldera has experienced persistent ground deformation, paired with increasing seismic magnitudes and rates since 2015. Recent geodetic and seismic measurements reveal a significant increase in uplift rates, shedding light on the spatial and temporal deformation patterns. The effects of magma transport on the measured deformation have been discussed, along with the presence of shallow gas and fluid accumulation, which also play a critical role in building the pressure up. Understanding the source of the observed deformation and seismic activity requires integrating diverse geophysical observations into geodynamic modeling, which provides crucial insights into the geophysical response of coupled tectonic and magmatic processes.

Joining the interpretations from seismic imaging, geodetic observations, and rock physics, we perform thermo-mechanical modelling of the Campi Flegrei magmatic system using the Lithosphere and Mantle Evolution Model (LaMEM) code, which takes into account visco-elasto-plastic rheologies. Employing the available structural information on the caldera, such as a caprock layer and a hydrothermal system, the 3D thermo-mechanical numerical simulations account for the realistic topography and a deep crustal magma migration from an ∼8 km deep magma sill to a magma reservoir at ∼ 5 km depth. Our approach also considers shallow gas and fluid accumulation, investigating the interaction between deep magma dynamics and overlying structures. The modelling results show how structural complexity influences the symmetry and amplitude of the deformation patterns and whether deep magma migration should be paired with the effect of shallow structures and rheologies. The findings suggest that integrating additional geophysical constraints could significantly improve our understanding of the deformation source and evolution of stress fields for future modelling of seismic responses. This integrated approach advances our comprehension of tectonic-magma interactions at Campi Flegrei caldera.