Strike-Slip Faulting in the Calabrian Accretionary Wedge: Using Analog Modeling to Test the Kinematic Boundary Conditions of Geodynamic Models

Abstract : The Calabrian accretionary wedge in the Ionian Sea is the site of slow deformation related to the overall convergence between Africa and Eurasia and the subduction zone beneath Calabria. High-resolution swath bathymetric data and seismic profiling image a complex network of strike-slip faults offshore Sicily. Ongoing normal faulting occurs in the straits of Messina area (1908 M7.2 earthquake). We applied analog modeling using granular materials in a compression box to test the predictions of certain geodynamic models regarding the location and kinematics of a major lateral slab edge tear fault. One experiment, using two independently moving backstops, showed that the relative kinematics of two blocks can produce a zone of dextral transtension and surface collapse in the model wedge. This experiment also produced a dextral offset in the deformation front. However, this offset is not observed in the morpho-bathymetry of the Calabrian accretionary wedge. In fact, counterclockwise material flow is observed along an internal boundary between the two corresponding lobes of the Calabrian wedge. The second experiment features an inner frictional (sand) wedge and an external viscoelastic wedge (sand and silicone) to attempt to model the interaction between the internal clastic portion and the external evaporitic portion of the Calabrian accretionary wedge. We interpret a major dextral offset in the limit between the external (evaporitic) wedge and the internal (clastic) wedge in the natural example, as well as other large-scale structural elements (elongated basin and a network of slip lines) as indicating the current primary kinematic boundary passes along the Alfeo Fault System and that the entire accretionary wedge remains tectonically active.
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https://hal.umontpellier.fr/hal-02318078
Contributeur : Gm Aigle <>
Soumis le : mercredi 16 octobre 2019 - 15:57:19
Dernière modification le : jeudi 17 octobre 2019 - 01:21:01

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Marc-André Gutscher, David Dellong, Stéphane Dominguez, Jacques Malavieille, David Graindorge, et al.. Strike-Slip Faulting in the Calabrian Accretionary Wedge: Using Analog Modeling to Test the Kinematic Boundary Conditions of Geodynamic Models. Transform Plate Boundaries and Fracture Zones, Elsevier, pp.321-337, 2019, ⟨10.1016/B978-0-12-812064-4.00013-X⟩. ⟨hal-02318078⟩

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