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The recent investigation carried out on the west bound of the Naples metropolitan area and inside the Campi Flegrei caldera as part of the Campi Flegrei Deep Drilling Project provided new insight in order to reconstruct the volcano-tectonic evolution of this extremely populated area. Campi Flegrei represents the highest risk volcanic areas in the world, although its volcano-tectonic structure, eruptive history and eruptive style of the largest eruptions are intensely debatedby scientists since several decades. We present here a summary of stratigraphic and geochronological dating (40Ar/39Ar) allowing to define the age of intra-caldera deposits belonging to the two highest magnitude caldera-forming eruptions (i.e. Campania Ignimbrite, 39÷40 ka, and Neapolitan Yellow Tuff, 14.9 ka) and to evaluate the amount of collapse of the eastern sector of the caldera.
These results point out: (i) a reduction of the area affected by caldera collapse, which appears to not include the city of Naples; (ii) a small volume of the infilling caldera deposits, particularly for the CI; and (iii) the need for reassessment of the collapse amounts and mechanisms related to larger eruptions. Our results also imply a revaluation of volcanic risk for the eastern caldera area, including the city of Naples. The results of this study point out that large calderas are characterised by complex collapse mechanisms and dynamics, whose understanding needs more robust constraints, which can be obtained from scientific drilling.
Ar dating, caldera dynamic, caldera-forming eruptions, Campi Flegrei caldera, CFDDP drilling, volcanic hazard
[1] Hill, D. P., Unrest in Long Valley Caldera, California, 1978–2004, in Mechanisms of activity and unrest at large calderas, edited by Troise et al., 269, pp. 1–24, Geological Society, London, Special Publication, 2006.
[2] Lowenstern, J.B., Smith, R.B. & Hill, D.P., Monitoring super-volcanoes: geophysical and geochemical signals at Yellowstone and other large caldera systems. Philosophical Transaction of the Royal Society A, 364, pp. 2055–2072, 2006. https://doi.org/10.1098/rsta.2006.1813
[3] Carlino, S. & Somma, R., Eruptive versus non-eruptive behaviour of large calderas: the example of CampiFlegrei caldera (southern Italy). Bulletin of Volcanology, 72, pp. 871–886, 2010. https://doi.org/10.1007/s00445-010-0370-y
[4] Carlino, S., Somma, R., Troise, C. & De Natale, G., The geothermal exploration of Campanian volcanoes: historical review and future development. Renewable and Sustainable Energy Reviews, 16, pp. 1004–1030, 2012. https://doi.org/10.1016/j.rser.2011.09.023
[5] Deino, A.L., Orsi, G., de Vita, S. & Piochi, M., The age of the Neapolitan Yellow Tuff caldera-forming eruption (CampiFlegrei caldera - Italy) assessed by 40Ar/39Ar dating method. Journal of Volcanology and Geothermal Research, 133, pp. 157–170, 2004. https://doi.org/10.1016/S0377-0273(03)00396-2
[6] Rosi, M. & Sbrana, A., PhlegreanFields: Petrography. Quaderni de La Ricerca Scientifica, 114, pp. 60–79, 1987.
[7] Perrotta, A., Scarpati, C., Luongo, G. & Morra, V., The CampiFlegrei caldera boundary in the city of Naples, in Volcanism in the Campania Plain: Vesuvius, CampiFlegrei and Ignimbrites, edited by De Vivo, B., pp. 85–96, Elsevier, Special Publication, 2006.
[8] Orsi, G., de Vita, S. & Di Vito, M., The restless, resurgent CampiFlegrei nested caldera (Italy): constraints on its evolution and configuration. Journal of Volcanology and Geothermal Research, 74, pp. 179–214, 1996. https://doi.org/10.1016/S0377-0273(96)00063-7
[9] Vitale, S. & Isaia, R., Fractures and faults in volcanic rocks (CampiFlegrei, southern Italy): insight into volcano-tectonic processes. International Journal of Earth Sciences, 103, pp. 801–819, 2014. https://doi.org/10.1007/s00531-013-0979-0
[10] Carlino, S., Kilburn, C.R.J., Tramelli, A., Troise, C., Somma, R. & De Natale, G., Tectonic stress and renewed uplift at CampiFlegrei caldera, southern Italy: new insights from caldera drilling. Earth and Planetary Science Letters, 420, pp. 23–29, 2015. https://doi.org/10.1016/j.epsl.2015.03.035
[11] De Natale, G., Troise, C., Pingue, F., Mastrolorenzo, G., Pappalardo, L. & Boschi, E., The CampiFlegrei Caldera: unrest mechanisms and hazards, in Mechanisms of activity and unrest at large calderas, edited by Troise et al., Geological Society, London, Special Publication, 269, pp. 25–45, 2006.
[12] Moretti, R., De Natale, G. & Troise, C., A geochemical and geophysical reappraisal to the significance of the recent unrest at CampiFlegrei caldera (Southern Italy). Geochemistry, Geophysics, Geosystems, 18, pp. 1244–1269, 2017. https://doi.org/10.1002/2016GC006569.
[13] De Natale, G. & Zollo, A., Statistical analysis and clustering features of the Phlegraean Fields earthquake sequence, May ‘83–May ‘84. Bulletin of the Seismological Society of America, 76, pp. 801–814, 1986. https://doi.org/10.1785/01.20120036
[14] Lipman, P.W., Subsidence of ash-flow calderas: Relation to caldera size and magmachamber geometry. Bulletin of Volcanology, 59, pp. 198–218, 1997. https://doi.org/10.1007/s004450050186