The Maddaloni/X-6 eruption stands out as one of the major events during the Late Pleistocene at Campi Flegrei

The CampiFlegrei caldera (Italy) is among the most productive volcanoes of the Mediterranean area. However,thevolcanichistoryprecedingtheVEI7CampanianIgnimbriteeruption(~40ka)isstillpoorly constrained. Here, we use a tephra dispersal model to reconstruct the eruption source parameters of the Maddaloni/X-6 eruption (~109 ka), one of the most widespread Late Pleistocene Mediterranean markertephrafromCampiFlegrei.Ourresultssuggestthattheeruptionwascharacterizedbyanearly Plinian phase involving ~6 cubic kilometers (within the range of 3–21 cubic kilometers) of magma, followed byaco-ignimbrite phaseerupting ~148cubickilometers(rangeof60–300cubickilometers). This ranks the Maddaloni/X-6 as a high-magnitude (M7.6) eruption, resulting at least as the second largest known event from Campi Flegrei. This study provides insights into the capability of the Campi Flegrei magmatic system to repeatedly generate large explosive eruptions, which has broad implications for hazard assessment in the central Mediterranean area.