BRIDGE aims at developing coordinated and multidisciplinary research with the final goal to yield a decisive step ahead in our current state-of-the-art of volcanic gas studies.

We propose in particular to combine technological innovations and modelling efforts in the final attempt to:

(i) refine existing techniques, and setting up new innovative technology, for the real-time high-rate (up to 1 Hz) observation of volcanic gas emissions.

In particular, we propose to:

- rely on recent progresses in UV imaging techniques (UV camera) to design and deploy in the field (at Etna and Stromboli volcanoes in Italy) the first permanent monitoring networks for high rate (1 Hz) SO2 flux observations. This UV camera networks will integrate the already available geophysical networks run by INGV (Etna) and Università di Firenze (Stromboli), and will therefore allow for creation – for the first time at any volcano observatory to date – of a real multi-disciplinary array of simultaneously acquired (at same location, and time) chemical and physical signals relevant to volcano monitoring;

- use the most recent advances in the LIDAR (light detection and ranging) technique to develop an innovative instrument for the direct remote measurement of the CO2 flux from volcanoes. More in the specific, we propose to design, develop in the laboratory, and using in the field (for the very first on an active volcano, to date) a LIDAR using an high-resolution OPO (Optical Parametric Oscillator) as the laser source. The instrument will be adapted and tuned to measure CO2 concentration profiles through sections of a volcanic plume using the differential absorption LIDAR (DIAL) technique.

(ii) promote a very first systematic and quantitative integration of volcanic gas and geophysical data; in particular, we plan to analyse our derived high-frequency time series for SO2 and CO2 fluxes in tandem with co-acquired seismic, thermal IR, and infrasonic data. Using automated cross-correlation and wavelet techniques, we will explore our dataset to look at relations and dependences between gas flux data and geophysical parameters (e.g., time trends in tremor and infrasonic amplitude, seismic displacement and IR signal irradiated by individual explosions).

(iii) use the above in-tandem geophysical-volcanic gas observations to obtain fundamental constraints into pre- to sin-eruptive volcanic processes, to refine/implement models of gas-magma flow in conduits, and to confine the source mechanisms controlling the generation and irradiation of seismic and infrasonic energy release at active volcanoes. Our real-time high-rate gas observations will be here used to search for definite answers to a number open issues in Volcanology, among which: is the magma rise-dependent model or the foam-layer model a most likely source mechanisms to account for Hawaiian- to Strombolian-style explosive activity at volcanoes? is gas release from volcanoes a steady, unsteady, or periodic process? And what would this (the former answer) tell us on the modes of gas-magma ascent in conduits? is volcanic tremor caused by sustained pressure transients in a coupled fluid-solid matrix, due to unsteady transport of magmatic fluids? Is the time-variable rate/energy of noise (infrasound) irradiated by volcanoes reflecting a change in the rates/modes of gas release at surface? Can we establish a clear gas-related link accounting for the large spectrum of explosive activity in nature?