3D modeling of an active normal fault network in the Apulian Plateau (offshore Capo Santa Maria di Leuca, Puglia, Italy).

@inproceedings{BistacchiGM2012,
 abstract = { The southernmost part of Puglia (Penisola Salentina) and the Apulian Plateau, which represents its offshore continuation, are characterized by thick cretaceous carbonatic sequences and discontinuous tertiary/quaternary deposits crosscut by a NNW-SSE penetrative normal fault system. Recent highresolution bathymetric and shallow seismic surveys have revealed that a relevant number of these faults crosscut the seabed, resulting in numerous fault scarps which appear to be roughly coeval with quaternary submarine landslides and coral-topped mounds. In this contribution we present the results of a 3D modeling study which was aimed at characterizing the geometry and architecture of this fault network, its age, and kinematics. The model was developed integrating data from different and heterogeneous sources: regional scale 2D seismics collected by oil companies in the '60s and '80s, three wells, more recent seismics collected during research projects in the '90s, very high resolution Sparker and Chirp data, high resolution multibeam bathymetry and samples collected on the seabed. The heterogeneity in the dataset resulted in numerous challenges regarding both technical details (e.g. georeferencing and importing several hundred kilometres of paper seismic profiles) and interpretation. Particularly interesting was the possibility to assess the 3D continuity of structures imaged in 2D seismics thanks to the occurrence of continuous fault scarps on the seabed. On the other hand, 2D seismics was fundamental in revealing the vertical extent and finite displacement associated to fault scarps imaged with multibeam bathymetry.
The complex geometry of a regional-scale Infra-Messinian reflector was finally modelled with implicit surface methods (StructuralLab plugin). However, not all structures that can be interpreted in 2D seismic profiles can be correlated with fault scarps, and this results in a relevant structural uncertainty in some portions of the model. In order to assess the effect of this uncertainty on our regional-scale conclusions, we have developed a set of simulations with the FaultMod plugin, which allows to generate stochastic fault networks under various assumptions. Particularly, we have used the better defined portions of the model as "training areas" for the stochastic model, limiting in this way the space of the fault network parameters to be investigated. As a general geological conclusion, we may say that the NNW-SSW normal fault network in the Apulian Plateau can be considered active (faults crosscut submarine landslides and coraltopped mounds dated at the Holocene-Pleistocene boundary), and that the cumulative horizontal displacement is consistent with a relevant WSW-ENE stretching associated to the bending moment applied to the Apulian Plate by the combined effect of the Appennines and Hellenides subduction.
From a methodological point of view, we confirm that a workflow based on implicit surfaces is very effective when reconstructing models at the regional scale from heterogeneous data sources, and that the FaultMod plugin allowed to explore the effect of structural uncertainty on geodynamic conclusions (e.g. the amount of WSW-ENE stretching). },
 author = { Bistacchi, Andrea AND C, Pellegrini AND Salvini, A. AND Marchese, F. },
 booktitle = { Proc. 32nd Gocad Meeting, Nancy },
 title = { 3D modeling of an active normal fault network in the Apulian Plateau (offshore Capo Santa Maria di Leuca, Puglia, Italy). },
 year = { 2012 }
}