Revised 3D crustal structure of Southern Italy: an integrated approach combining geophysical and petrophysical constraints

The Southern Italy, a tectonically active region of significant geodynamic importance, is also a critical area for seismic hazard assessment and sustainable resource management. Characterized by lithospheric convergence, crustal delamination, active fault systems and a complex tectonic style made up of the eastward thrusting of different, once adjacent, geographic paleo-domains, the area faces considerable seismic risks. These features make the Southern Apennines, and thus the Southern Italy, an ideal yet complex laboratory for constructing an integrated 3D geometrical model to address structural complexities and support hazard mitigation efforts, where the significance of the results justifies the challenges inherent in the integration process.

This study integrates geological and geophysical data to develop an integrated 3D crustal model for the Southern Apennines area, with a spatial resolution of 5x5x1 km³, along East, North and depth, respectively. Our analysis synthesizes stratigraphic, geophysical, and structural data into a unified framework for regional geological interpretation. Key datasets include stratigraphic well logs (ViDEPI project consultable at the page: https://www.videpi.com/videpi/pozzi/pozzi.asp), lithological maps, seismic tomographic models, gravity and magnetic models, and thermal and petrophysical constraints. These datasets underwent rigorous filtering, analysis and gridding to ensure consistency across spatial scales. The methodology incorporates thermal varying gradients, P-wave velocity variations, and depth-dependent corrections, enabling the identification of major intra-crustal discontinuities and lithological transitions.

Model construction involved delineating the main lithological units, including sedimentary covers, carbonate platforms, and crystalline basement domains, extending down to the Moho depth. Validation was performed by comparing model outputs with independent borehole data and geophysical data interpretation, achieving high accuracy and resolution. By synthesizing diverse datasets into a cohesive framework, this study addresses gaps in lithologic unit characterization throughout the study area and subsurface property predictions.

The Integrated 3D geological model is a versatile tool for addressing both scientific and social challenges. It supports thermo-rheological modelling, enabling detailed analyses of brittle-ductile transitions and their implications for seismic hazards. These results represent some of the goals of the PRIN2022 PNRR entitled “Relation between 3D Thermo-Rheological Model and Seismic Hazard for Risk Mitigation in the Urban Areas of Southern Italy – TRHAM”. The model also holds significant promise for practical applications, such as green energy initiatives, particularly geothermal resource exploration, by linking geodynamic processes to sustainable development in Southern Italy.