Dyke propagation scenarios feeding the Monte Nuovo eruption (1538 CE) at Campi Flegrei caldera (Italy): insights into magma dynamics and implications for unrest.

The 1538 Monte Nuovo event — the most recent eruption at Campi Flegrei —represents a key benchmark for understanding volcanic unrest at the caldera. Its preparatory phase exhibits significant parallels with modern non-eruptive unrest episodes (1950–1952, 1969–1972, 1982–1984) and the ongoing crisis (2005–present). While historical accounts, archaeological records, and field observations have previously allowed for detailed reconstructions of the pre-eruptive activity, these have largely provided static quantitative snapshots of pre-eruptive phases. This study translates these reconstructions into a physics-based modeling framework for Monte Nuovo pre-eruptive dynamics. We simulate the magma transport process during the two-year lead-up to the eruption, focusing on the propagation of a magmatic intrusion from a central shallow sill (~3 km depth) to the peripheral Monte Nuovo vent (~4 km away from the sill center). Our results test the robustness and consistency of previous findings, and isolate the effect of magma dynamics to the ground deformation, providing new insights on the magnitude of the magmatic vs hydrothermal contributions to uplift signals. This work offers critical implications for interpreting modern monitoring data and evaluating possible scenarios of unrest evolution should a Monte Nuovo-like event become increasingly probable.