Magmatic fluids uprise through ring faults at Campi Flegrei caldera

The progressive increase of ground deformation, seismicity, and gas emission is marking a remarkable unrest at Campi Flegrei caldera. The direct involvement of magma has been invoked to explain the deformation and space/time changes of velocity anomalies at shallow crustal depths. A challenging aspect is to forecast possible scenarios for the upward migration of magmatic fluids from the source at depth. Here, we show that the most recent seismicity (period 2023–2024), derived by a machine-learning-based earthquake detection procedure, aligns on a continuous set of caldera rim faults and on top of an inflating magma source. Direct channeling of magma through such ring faults can be a way to feed future eruptions, as observed in other calderas and inferred for the Mt. Nuovo historical eruption.