Conclusions
In creating the sand models, all the analysis and measurements performed on them helped us to better understand the kinematics of the geological context we aimed to reproduce (Bonini et al., in prep) and to put forward hypotheses on the seismotectonic setting of the study area.
Nevertheless, some items appeared during the study for which we did not find suitable and complete explanations. The maps of the models and all internal sections proved to be inadequate to analyze and interpret some of the more complex and hidden aspects that have been outlined above. For these reasons, a digital 3D reconstruction of the models has been developed in the firm belief that only a continuous and complete view could help to better understand the whole structure and kinematics of the sand-box experiments and of the reproduced tectonic setting itself.
The main points we found in using 3D models are:
Without a 3D reconstruction, it would be impossible to follow the path of the faults inside the model. The move models are fundamental to visualize the presence and the attitude of all faults.
On the internal sections of the models, it is possible to view the displacements of the faults. Some variations on these displacements are evident (there are differences on the amount of displacement) and it is useful to follow them through the whole model. The analysis of the different displacements on the single internal 2D sections is possible but not as useful and "self-evident" as the observation of the 3D reconstruction of the topography and fault planes.
The most evident result was the change of the topography in the middle part of the models with the increase in the imposed basal displacement. The depression could be detectable from the sections only, but it is evident how a 3D digital reconstruction with a colour scale enables a better visualisation and comprehension of the amount of the topographic depression, of its extension and progressive evolution through the different steps of the model. With a digital 3D continuous reconstruction, it is possible to compare the path of the fault displacements with the topographic variations to verify if it is directly related to the nature of faults or mainly related to "dilation effects" of the sand.