QP and QS of Campi Flegrei from the inversion of rayleigh waves recorded during the SERAPIS project

Abstract

Seismic shots recorded during the SERAPIS experiment were used to search a 1D elastic and inelastic model of the Gulf of Pozzuoli, south of the CampiFlegrei caldera. Waveforms were gaussian filtered in the range 5-8 Hz with afrequency step of 0.5 Hz and a half-width of the filter equal to 0.5 Hz. A cleardispersion of the most energetic propagation mode was revealed. This pro-perty of the surface wave in the gulf of Pozzuoli was theoretically reprodu-ced using the classical wave-number technique. To infer the best fit propaga-tion model, we developed a semi-automated procedure of fitting of filteredtraces with progressive adjustment of the model. The quality of the fitting wasestimated using the semblance among each couple of waveform (syntheticand observed). Our formulation allowed us also to estimate the error onmodel parameter by mapping the noise on seismograms on the semblance. The obtained 1D model confirms that in average intrinsic Qp at the CampiFlegrei caldera is of the order of 300-500 which is a background value higherthan that of other volcanic areas. This report is a summary of a part of the phd thesis in Earth Sciences atUniversity of Bari of Maria Trabace.