In this paper, a 1:5000 map of the geomorphic consequences of the 14th–15th October 2015 flash flood is presented. The most severely affected area (about 13 km²) was located at the footslope of Mt. Camposauro (Southern Italy), between the municipalities of Solopaca and Paupisi. In this area high-intensity and very localized cloudbursts of short duration induced hillslope erosion and sediment delivery from the slopes to the Calore River, activating several alluvial fans. The rainstorm lasted 7 h with a maximum recorded rainfall peak of nearly 140 mm in 2 h. The event map resulting from a geological and geomorphological post-event field survey was supported by satellite images and unmanned aerial vehicle image interpretations, respectively taken one day and one week after the event. The flash flood resulted in no casualties but severely affected the local economy, mainly based on agriculture and wine production.

Campi Flegrei is a densely populated volcanic area in Italy. Its inner caldera periodically experiences uplift and subsidence, known as bradyseism, also accompanied by seismic activity. In the last decade, with uplift rates up to 2 cm/month, about nine-thousand earthquakes were recorded. Upon request of the local administration, the most updated data were collected and analyzed to evaluate the risk management strategy consisting of structural retrofitting according to the building code. Here it is shown that the reference moment magnitude is in the range \(\left({{\mathrm{4.4,5.1}}}\right)\), based on fault mapping, geomorphological inference, earthquake relocation, stress-drop analysis, and ground motion modelling. Earthquake forecasting enabled computing the exceedance probabilities of these magnitudes. Earthquake engineering showed that the minimum magnitudes expected to cause exceedance of design ground motion, are larger than the reference magnitudes. Finally, the risk reduction implied by the safety levels of new constructions was assessed for reinforced concrete buildings.