The Permanent Monitoring System of the Campi Flegrei Caldera, Italy

Abstract

We present the main features of the permanent monitoring system managed by the Istituto Nazionale di Geofisica e Vulcanologia-Osservatorio Vesuviano in the Campi Flegrei caldera. Eruptive history of this active volcano shows that the majority of the eruptive events has been characterised by high explosivity and was accompanied by pyroclastic density currents. Its last eruption occurred in AD 1538 and in the next centuries the Campi Flegrei caldera has experienced several episodes of bradyseism and also the progressive increasing of the urbanisation in the area (west of Naples). Monitoring the dynamics of a mainly explosive volcano completely embedded in a very populated area is a challenging task. In order to detect any variation in the physical and chemical parameters of the Campi Flegrei caldera, the Istituto Nazionale di Geofisica e Vulcanologia-Osservatorio Vesuviano manages a permanent multi-parametric monitoring system. All the recorded h24 continuous data are transmitted to the Monitoring Room of the Osservatorio Vesuviano in Naples, where they are acquired, processed and evaluated to define changes in the dynamical state of the volcano. The caldera, since the end of 2004, is experiencing a bradyseismic episode characterised by a low velocity rate uplift, low energy earthquakes and increasing in the magmatic components of fumarolic fluids. The monitoring and surveillance activity of the Campi Flegrei caldera plays a crucial role in the volcanic emergency plan that includes evacuation of approximately 500,000 people before the beginning of the eruption.