3D velocity model of Ischia island from the inversion of active seismic data,

Eruption scenarios can be constructed based on the detailed knowledge of the vol- canic structure, as represented by the elastic/attenuation, thermal, density and other geophysical parameter distribution. The objective of the research is the definition of a 3D crustal model of the Ischia volcanic region, by tomography analysis, and the identification and detection of the possible crustal reservoir of magma feeding. Is- chia island, whose last eruption occurred in 1301 A.D., belongs to the Campi Flegrei volcanic area located into the Campania Plain (southern Italy). Recently, a project (SERAPIS) of active seismic was performed in the Campi Flegrei caldera and surroundings using off-shore seismic energization and data acquisition on the sea-bottom and on land. An area centered on Ischia island have been selected and data recorded at eight seismic stations located on land and four located on sea-bottom have been analyzed. We performed a manual reading of about 10,000 first P wave arrival times on the waveforms band-pass filtered between 5 and 15 Hz. We have used the tomographic code developed by Benz et al. based on a linearized iterative approach, applied on several areas in the world. The method uses the finite differences technique to compute travel times by solving the Eikonal equation which provides a fast and accurate tool even in highly heterogeneous media. We present preliminary images of the structural model including resolution analysis relative to different model parameterizations.