: We report a direct comparison of scaled analogue experiments to test the reproducibility of model results among ten different experimental modelling laboratories. We present results for two experiments: a brittle thrust wedge experiment and a brittleviscous extension experiment. The experimental set-up, the model construction technique, the viscous material and the base and wall properties were prescribed. However, each laboratory used its own frictional analogue material and experimental apparatus. Comparison of results for the shortening experiment highlights large differences in model evolution that may have resulted from (1) differences in boundary conditions (indenter or basal-pull models), (2) differences in model widths, (3) location of observation (for example, sidewall versus centre of model), (4) material properties, (5) base and sidewall frictional properties, and (6) differences in set-up technique of individual experimenters. Six laboratories carried out the shortening experiment with a mobile wall. The overall evolution of their models is broadly similar, with the development of a thrust wedge characterized by forward thrust propagation and by back thrusting. However, significant variations are observed in spacing between thrusts, their dip angles, number of forward thrusts and back thrusts, and surface slopes. The structural evolution of the brittle-viscous extension experiments is similar to a high degree. Faulting initiates in the brittle layers above the viscous layer in

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Analog models provide a useful tool to investigate on the three-dimensional evolution of geodynamic processes. In this contribution, we describe the results of an experimental program designed for studying the progression through time of lithosphere thinning and necking. In particular, by exploiting the three-dimensional real-time information on surface topography and base lithosphere geometry provided by paired top and bottom laser scanning, we studied the evolution of lithosphere necking at low and fast asymmetric plate divergence. Our results indicate that this parameter plays a fundamental control on the incremental and finite slope of the lithosphere necking. Influences are discussed on the application of experimental data to natural rift system.

[1] Lithosphere necking evolution determines the 3-D architecture of crustal and upper mantle thinning and related basins, and the heat flow distribution in rifted regions. Despite a large number of studies, lithosphere necking evolution is still a matter of debate. We present the result from lithospheric-scale analog models designed for investigating the necking shape during extension and the vertical distribution of finite deformation in the mechanical lithosphere. In our experiments, lithosphere necking is asymmetric and, in particular, the 3-D distribution of thinning is cylindrical in the crust and very heterogeneous in the mantle. Overall, the evolution of rifting and necking progresses from delocalized to localized deformation.

The structural framework of the Val d’Agri region results from the superposition of different deformation events over time. In this area, the largest European onshore oil field was discovered in the 1980s, and since then, much geologic and geophysical data have been collected. However, the structural complexity and the poor quality of subsurface data have prevented a full understanding of fault evolution and kinematics so far. In this study, scaled sandbox analogue models have been used to better understand the role of syn-rift inheritance in the present-day structural architecture and to test different possible mechanisms of interaction between inherited transpressional structures at depth and newly formed extensional fault systems at shallow levels during regional quaternary extensional tectonics. Analogue models included two consecutive sinistral transpressional phases deforming the basement and the overlying Apulian Platform carbonates, affected by preexisting northeast–southwest-oriented extensional fault zones. The third phase of the experiments consisted of extensional reactivation of the previously formed transpressional structures. Different kinematic solutions were used to investigate the causal relationships between deep and shallow deformation structures. The very good similarity between the experimental results and the natural prototype strongly supports the presence at depth of a main northeast–southwest-oriented syn-rift extensional fault zone, which was affected by positive inversion during the transpressional deformation of the Apulian Platform below the Val d’Agri area. Comparison of experimental results with fault patterns interpreted on available seismic lines indicates that, despite that no direct connection from deep to shallow faults has been recognized, some structural control of the fault pattern at depth on the evolution of the Val d’Agri quaternary extensional fault systems at shallow depth is possible. Extensional deformations at depth can be accommodated by newly formed faults or by the extensional reactivation of inherited high-angle transpressional fault zones.