Distributed dynamic strain sensing has been demonstrated to be useful to record and locate earthquakes, in particular using existing Telecom fibre optic networks. In urban areas, as the deployment of conventional seismometers is particularly challenging, mainly because of high noise conditions and difficulties in finding adequate locations, the existence of fibre optic telecom network to be repurposed as array of seismic sensors makes DFOS (Distributed Fiber Optic Sensing) attractive. Here we report observations in the Napolitean volcanic area of Napoli and Campi Flegrei, Italy. In order to enhance the monitoring of the current unrest (increased seismic activity and deformation) observed since 2005, we interrogated two telecom fibre optic cables crossing the Campi Flegrei active seismic...