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QP and QS of Campi Flegrei from the inversion of rayleigh waves recorded during the SERAPIS project
Author(s)
Sponsors
I.N.G.V.
Language
English
Obiettivo Specifico
1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
Status
Published
Peer review journal
No
Issued date
2007
Series/Report No.
INGV- DPC/V4 PROJECT V4
Keywords
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.
This report is a summary of a part of the phd thesis in Earth Sciences atUniversity of Bari of Maria Trabace.
References
S. de Lorenzo, A. Zollo, M. Trabace, M. Vassallo
Very interestingly the main energy content is very well reproduced by themodel and, more interestingly, the repartition of the energy in at least two pro-pagation modes, is also well reproduced, in particular at the OBS 46. The value of semblance increases of 28% from the initial model to the final one.
CONCLUSION
Qp values in the four thin layers is generally in the order of 100-200 which is roughly the same magnitude order of the average values previously inferredfrom a tomographic study of the Campi Flegrei caldera (de Lorenzo etal.,2001), whereas only a very high Qp (Qp=900) is inferred between 0.25 and0.5 km. Vp values inferred for the first layer are slightly lower than those obtai-ned by Judhenerc and Zollo (2004).
REFERENCES
Bouchon, M., 1981, Bull. Seism. Soc. Am. 71, 959-971.
de Lorenzo, S, Iannaccone, G, Zollo, A., Journal of Seismology 7: 49-64, 2003.de Lorenzo, S., A. Zollo, and F. Mongelli (2001), J. Geophys. Res., 106, 16,265-16,286.Dziewonski, A.M. and Hales, A.L., 1972, Numerical analysis of dispersed seismic waves,in: Bolt, B.A. (ed.), Methods of computational physics 11: Seismology: surface wavesand earth oscillations, Academic Press, New York and London, 309 pp.Judenherc and A. Zollo, J. Geoph. Res. Vol. 109, B10312, DOI:10.1029/2003JB002876,2004.
Nolet, G., 1990, J. Geophys. Res. 95, 8499-8512.Telford, W.M., Geldart, L.P., Sheriff, R.E. and Keys, D.A., 1990, Applied geophysics. 2ndedn. Cambridge University Press, Cambridge.Yao, P.C. and Dorman, J., 1992, Bull. Seism. Soc. Am. 82, 962-979.
Zollo A., S. Judenherc, E. Auger, L. D’Auria, J. Virieux, P. Capuano, C. Chiarabba, R. DeFranco, J. Makris, A. Michelini, and G. Musacchio, Geophysical Research Letters, Vol.30, No. 19, 2002, DOI:10.1029/2003GL018173, 2003.
Very interestingly the main energy content is very well reproduced by themodel and, more interestingly, the repartition of the energy in at least two pro-pagation modes, is also well reproduced, in particular at the OBS 46. The value of semblance increases of 28% from the initial model to the final one.
CONCLUSION
Qp values in the four thin layers is generally in the order of 100-200 which is roughly the same magnitude order of the average values previously inferredfrom a tomographic study of the Campi Flegrei caldera (de Lorenzo etal.,2001), whereas only a very high Qp (Qp=900) is inferred between 0.25 and0.5 km. Vp values inferred for the first layer are slightly lower than those obtai-ned by Judhenerc and Zollo (2004).
REFERENCES
Bouchon, M., 1981, Bull. Seism. Soc. Am. 71, 959-971.
de Lorenzo, S, Iannaccone, G, Zollo, A., Journal of Seismology 7: 49-64, 2003.de Lorenzo, S., A. Zollo, and F. Mongelli (2001), J. Geophys. Res., 106, 16,265-16,286.Dziewonski, A.M. and Hales, A.L., 1972, Numerical analysis of dispersed seismic waves,in: Bolt, B.A. (ed.), Methods of computational physics 11: Seismology: surface wavesand earth oscillations, Academic Press, New York and London, 309 pp.Judenherc and A. Zollo, J. Geoph. Res. Vol. 109, B10312, DOI:10.1029/2003JB002876,2004.
Nolet, G., 1990, J. Geophys. Res. 95, 8499-8512.Telford, W.M., Geldart, L.P., Sheriff, R.E. and Keys, D.A., 1990, Applied geophysics. 2ndedn. Cambridge University Press, Cambridge.Yao, P.C. and Dorman, J., 1992, Bull. Seism. Soc. Am. 82, 962-979.
Zollo A., S. Judenherc, E. Auger, L. D’Auria, J. Virieux, P. Capuano, C. Chiarabba, R. DeFranco, J. Makris, A. Michelini, and G. Musacchio, Geophysical Research Letters, Vol.30, No. 19, 2002, DOI:10.1029/2003GL018173, 2003.
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