The Calcari Grigi carbonate platform formed on one of the highs that were outlined during the Early Jurassic rifting in the area now occupied by the Italian Southern Alps. Rocks were brought to the surface by Alpine orogenesis, but escaped strong deformation and metamorphism leaving preserved the original paleogeographic setting. The Calcari Grigi Group is now exhumed  in an area ~100km x 100km wide and comprises the marine shallow-water sedimentary rocks deposited in several platform sub-environments (tidal flats, deep lagoons, oolitic shoals etc.). Good outcrop continuity, extensive geological mapping carried out during the last decade and previous studies provide a great wealth of field-information on this geologic body.

A striking feature of the carbonate platform is represented by the evidence of active syn-sedimentary tectonics testified by exposed structure. Despite the good outcrop conditions, however, the reconstruction of the Early Jurassic faultnetwork is particularly challenging because direct evidences of syn-sedimentary faults are sparse and discontinuous. To  the  end of exploring the characteristics of this ancient fault-network useful information can be obtained from the analysis of the spatial distribution of the thicknesses of the platform units. Indeed different cumulative subsidence was reflected in the creation of variable accommodation space and thus in sharp changes in sediments’ thickness. Spatial analysis reveals an organization in the thickness variability and helps to retrieve information about the arrangement of the Jurassic fault-system that drove subsidence during the platform growth. This permits to estimate the position of main Jurassic faults and reveals an extensive orthorhombic fault-network at the platform scale. This fault arrangement suggests a true 3D strain field that could shed new light on the rifting mechanisms in the South Alpine.

3D modelling was carried out with SKUA® geomodeling software and allows to estimate fault throws helping in investigating the past degree of linkage of the ancient faults. Moreover modelling of main stratigraphic horizons permits to model the 3D geometry of the sedimentary prisms outlined by the main faults. Facies information derived from field investigations can now be used to populate the model and will represent the starting point to evaluate if tectonics influenced the sedimentary environments. A field data-based model of a carbonate platform of this size potentially represents a useful analogue for carbonate reservoirs and could help the understanding of the evolution of similar present and buried sedimentary bodies.

Il forte terremoto che ha colpito il Giappone nel 2011 ha dimostrato che, contrariamente a quanto comunemente ritenuto, anche i sedimenti più vicini alla superficie possono essere sede deformazioni cosismiche molto importanti. Ciò ha contribuito ad un rinnovato interesse nello studio delle possibili evidenze fossili di terremoti preservate in sedimenti sciolti o poco consolidati, allo scopo di incrementare le conoscenze paleosismologiche in regioni esposte a rischio sismico. In questo contributo saranno illustrate le caratteristiche strutturali e petrofisiche di una zona di faglia da noi scoperta nel settore occidentale del bacino dell’Aquila, con particolare riguardo alla presenza di importanti fenomeni di paleofluidizzazione dei sedimenti che, unite alle peculiari caratteristiche delle superfici di taglio, suggeriscono l’azione di terremoti di magnitudo superiore a 7.0 durante il Pleistocene medio.

I will describe laboratory experiments on the frictional slip along a rough and spatially extended interface. Utilizing simultaneous measurements of the real area of contact together with measurements of the spatial profile of the stresses adjacent to the interface, we can perform real-time observations of how interface ruptures that lead to slip events take place. We will present real-time observations of the how slip is born. We observe distinct modes of interface rupture and relate their propagation velocity to stresses along the interface that exist prior to rupture nucleation. These include ruptures that are limited by the Rayleigh wave speed of the material, supershear ruptures and slow rupture fronts that propagate at velocities that are nearly two orders of magnitude more slowly. These modes should be akin to rupture modes that occur along natural faults.

We will also present new results on the structure of the stress fields that surround rupture tips while they are propagating. These demonstrate that many features of these fields can be quantitatively described by classic fracture mechanical solutions describing shear fracture.