GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.2 GNGTS 2024 Fig. 2 – Power Spectral Density (PSD) (panel a) and Pressure Power Spectrum (panel b) of 04/10/2022. The Spectrum analysis allows us to identfy the main features of the vent, characterised by bubbles radii of 0.02 m that produce the main energetc peak centered at ~250 Hz, also visible in the Spectrogram along with smaller bubbles that produce less energetc peaks up to 2 kHz. Therefore, in the algorithm, we take into consideraton a wide frequency range, spanning from 150 Hz to 2250 Hz, in order to estmate all the gas released by the vent. The Spectrogram confrms that the energy spans in a wide bandwidth which is compatble with the size of the bubble observed. In this framework, the inversion algorithm was applied to the dataset, considering the frequency range from 150 to 2250 Hz, as shown in Fig. 3. Fig. 3 – Charts showing the Spectrograms recorded on 04/10/2022 on which the inversion range is indicated (red lines). The fow emission rate estmated through the inversion algorithm, which assumes a mean value of 8.32 liters per minute, is in good agreement with the direct observatons. This confrms that