Daniele Cirillo

Ground deformation and source geometry of the 24 August 2016 Amatrice earthquake (Central Italy) investigated through analytical and numerical modeling of DInSAR measurements and structural-geological data

We investigate the ground deformation and source geometry of the 2016 Amatrice earthquake (Central Italy) by exploiting ALOS2 and Sentinel-1 coseismic differential interferometric synthetic aperture radar (DInSAR) measurements. They reveal two NNW-SSE striking surface deformation lobes, which could be the effect of two distinct faults or the rupture propagation of a single fault. We examine both cases through a single and a double dislocation planar source. Subsequently, we extend our analysis by applying a 3-D finite elements approach jointly exploiting DInSAR measurements and an independent, structurally constrained, 3-D fault model. This model is based on a double fault system including the two northern Gorzano and Redentore-Vettoretto faults (NGF and RVF) which merge into a single WSW dipping fault surface at the hypocentral depth (8 km). The retrieved best fit coseismic surface deformation pattern well supports the exploited structural model. The maximum displacements occur at 5–7 km depth, reaching 90 cm on the RVF footwall and 80 cm on the NGF hanging wall. The von Mises stress field confirms the retrieved seismogenic scenario.

Geology map of the central area of Catena Costiera: insights into the tectono-metamorphic evolution of the Alpine belt in Northern Calabria

The 1:25.000 scale geological map of the central area of Catena Costiera aims to provide a picture of the tectonic setting of the metamorphic units belonging to the Alpine collisional belt of Northern Calabria, Italy. The exposed successions of the study area have been investigated by structural analyses, petrographic, petrological and geochemical studies whose results are summarised in the geological map. In this area, two HP-LT metamorphic, oceanic-derived units, referred as the Mongrassano and Cozzo Cervello units, have been distinguished on the base of their stratigraphic and tectono-metamorphic evolution. Both the oceanic-derived units show a polyphase deformation history developed under retrograde metamorphism in a subduction zone by underplating and exhumation into an accretionary wedge. These units are overthrust by continental-derived units, referred as the Sila and Castagna units, consisting of medium and high-grade metamorphic rocks. While the Castagna unit displays an Alpine HP/LT metamorphic overprint, the Sila unit escaped any subduction-related metamorphism.

Structural style of Quaternary extension in the Crati Valley (Calabrian Arc): Evidence in support of an east-dipping detachment fault

New geological field data, integrated with commercial seismic lines, allowed us to constrain the geometry and time-space evolution of the fault system that ruled the tectono-sedimentary evolution of the NS-striking Crati graben, in the axial portion of the northern Calabrian Arc.We highlight that this basin is controlled by a 60-km long east-dipping master fault, referred to as the Crati Graben Detachment Fault (CGDF).On the seismic sections, the CGDF appears as an east-dipping low-angle reflection reaching the surface along the eastern slope of the Catena Costiera Calabra. Its surface expression corresponds to an alignment of moderately-inclined (30° to 45°) left-stepping en-echelon faults.More to the East, a number of E- and W-dipping high-angle normal faults branch upward from the CGDF. Their reconstructed timing suggest that the westernmost faults are active since the Early Pleistocene and show a progressive eastward rejuvenation trend.The conversion to depth of a W-E oriented seismic section, crossing the entire Crati graben, highlights that the CGDF has a staircase geometry, with an average angle of 30°, and reaches a depth of 7-8 km below the east side of the basin. The evolutionary stages of the related fault system were reconstructed by restoring the section through the Move suite software (Midland Valley Exploration), in order to verify the kinematic consistency of our subsurface interpretation and estimate the amount of associate extension.Finally, the present activity and the possible seismogenic role of the CGDF is preliminarily discussed, by comparing the geometry of the extensional fault system with the available historical and seismological instrumental datasets.