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First geophysical evidence of magma chamber beneath Campi Flegrei caldera through receiver functions analysis.

V. Ortega-Ramos1\,3, L. D'Auria1,2, J.L. Granja-Bruña3, I. Cabrera-Pérez4, L. Pappalardo5, G. Buono5 and N. M. Pérez1,2

  • Affiliations: 1Instituto Volcanológico de Canarias (INVOLCAN), 38600 Granadilla de Abona, Tenerife, Canary Islands, Spain. 2Instituto Tecnológico y de Energías Renovables (ITER), 38600 Granadilla de Abona, Tenerife, Canary Islands, Spain. 3Universidad Complutense de Madrid (UCM), 28040 Madrid, Spain. 4University of Geneva, Department of Earth Science, Geneva, Switzerland. 5Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy. 

  • Presentation type: Poster

  • Presentation time: Friday 16:30 - 18:00, Room Poster Hall

  • Poster Board Number: 223

  • Programme No: 3.10.21

  • Theme 3 > Session 10

Abstract

The receiver function analysis (RF) is a well-established method to investigate the crustal and upper mantle structure. It is sensitive to seismic discontinuities and provides information about P and S-wave velocities. In this work, we study the crust and the upper mantle of Campi Flegrei Caldera (CFc) up to 50 km depth. The CF volcanic system has a complex plumbing system, possibly consisting of different sources. It is important to consider that the volcano has been showing, since decades ago, signs of unrest with episodes of ground deformation, degasification, and seismicity. We obtained the RF from thirteen stations using multi-taper deconvolution and we applied the transdimensional approach of Bodin et al. (2012) to determine 1D profiles of P and S-wave velocities and the probability of a discontinuity beneath each station. Although, we use petrological data to study the liquid fraction in our geophysical model. We observe a low-velocity zone beneath CF ranging from 8 to 16 km of depth with an extension of 4 x 5 x 12 km and a partial melt fraction up to 5%. Below the crust, we observe a low-velocity layer with a thickness of about 5 km. This layer dips southward, with its top located at a depth of about 16 km at the northernmost point and 23 at the southernmost. The melt fraction ranges from 15 to 30% within this layer. These results highlight for the first time the structure of the whole magmatic plumbing system at Campi Flegrei, from mantle to upper crust.