Calderas are collapse structures related to the emptying of magmatic reservoirs, often associated with large eruptions from long-lived magmatic systems. Understanding how magma is transferred from a magma reservoir to the surface before eruptions is a major challenge. Here we exploit the historical, archaeological and geological record of Campi Flegrei caldera to estimate the surface deformation preceding the Monte Nuovo eruption and investigate the shallow magma transfer. Our data suggest a progressive magma accumulation from ~1251 to 1536 in a 4.6 ± 0.9 km deep source below the caldera centre, and its transfer, between 1536 and 1538, to a 3.8 ± 0.6 km deep magmatic source ~4 km NW of the caldera centre, below Monte Nuovo; this peripheral source fed the eruption through a shallower source, 0.4 ± 0.3 km deep. This is the first reconstruction of pre-eruptive magma transfer at Campi Flegrei and corroborates the existence of a stationary oblate source, below the caldera centre, that has been feeding lateral eruptions for the last ~5 ka. Our results suggest: 1) repeated emplacement of magma through intrusions below the caldera centre; 2) occasional lateral transfer of magma feeding non-central eruptions within the caldera. Comparison with historical unrest at calderas worldwide suggests that this behavior is common.

A multidisciplinary survey was carried out on the quality of water and sediments of the estuary of the Sele river, an important tributary of the Tyrrhenian Sea, to assess anthropogenic pressures and natural variability. Nine sediment sites were monitored and analyzed for granulometry, morphoscopy, benthic foraminifera and ostracod assemblages, heavy metals, and polycyclic aromatic hydrocarbons. Surface water was assayed for ionic composition and phytoplankton biomass. Total organic carbon (TOC) and total nitrogen (TN) in sediments were higher in the inner part of the estuary (IE), up to 12.7 and 0.7% because of anthropic influence. In waters, N-NH₄, N-NO₃, and P_tot. were high, with loads of P_tot in IE exceeding ~fourfold the limit. Here, it was also observed that the highest primary production was Chl-a, 95.70 µg/L, with cryptophytes, 37.6%, and diatoms, 33.8%, being the main phytoplanktonic groups. The hierarchical analysis split the estuary into two areas, with marked differences in anthropic pollution. Waters were classified as poor–bad level with respect to the content of nutrients. Sedimentological assay reveals littoral erosion and poor supply of river sandy sediments. The erosion environment is confirmed by the presence of meiobenthic recent marine forms intrusion inside the river. All these data reveal the fragility of the estuary and the need of urgent remediation actions.