Combined analysis of seismic and gravimetric data in the Adriatic plate

The presence of a structural heterogeneity between the northern part of the Adriatic plate (Central Mediterranean) and its southernmost sector was hypothesised by different authors and also confirmed recently by 3D velocity models obtained through surface wave tomography and local earthquake tomography. However, the seismological data leave some uncertainty about the location of the lateral limits of this heterogeneity and about its “structural” meaning. alysis of the Bouguer anomalies observed on a profile running from NW to SE along the Italian side of the plate has allowed to obtain a laterally improved and better constrained integrated model of the area. In particular, the gravimetric data have been interpreted through a 2(1/2)D density modelling developed adopting the seismic tomography model as starting point: the obtained results support the hypothesis of a 10 km thinning of the crust from NW to SE, compensated by the presence of a thick transition zone under the crust in the southern part of the Adriatic plate. The location of the boundary of this lateral heterogeneity was better defined, being marked by an increase of the Bouguer anomalies. timated density contrasts of the transition zone with respect to the contiguous layers of lower crust and mantle (about +0.5 and −0.1 g/cm3, respectively) and the comparison with the corresponding velocity contrasts, suggest that the material constituting this transition zone might have a composition more similar to that of the mantle.