We present the first regional map of CO2 Earth degassing from a large area (most of central and south Italy) derived from the carbon of deep provenance dissolved in the main springs of the region. The investigation shows that a globally significant amount of deeply derived CO2 (10% of the estimated global CO2 emitted from subaerial volcanoes) is released by two large areas located in western Italy. The anomalous flux of CO2 suddenly disappears in the Apennine in correspondence to a narrow band where most of seismicity concentrates. Here, at depth, the gas accumulates in crustal traps generating CO2 overpressurized reservoirs which induce seismicity.

We present a lattice QCD calculation of the charge diffusion coefficient, the electrical conductivity and various susceptibilities of conserved charges, for a range of temperatures below and above the deconfinement crossover. The calculations include the contributions from up, down and strange quarks. We find that the diffusion coefficient is of the order of 1/(2πT ) and has a dip around the crossover temperature. Our results are obtained with lattice simulations containing 2+1 dynamical flavours on anisotropic lattices. The Maximum Entropy Method is used to construct spectral functions from correlators of the conserved vector current.

A lattice calculation is presented for the electrical conductivity σ of the QCD plasma with 2+1 dynamical flavors at nonzero temperature. We employ the conserved lattice current on anisotropic lattices using a tadpole-improved clover action and study the behavior of the conductivity over a wide range of temperatures, both below and above the deconfining transition. The conductivity is extracted from a spectral-function analysis using the maximal entropy method, and a discussion of its systematics is provided. We find an increase of σ/T across the transition.

Abruzzi region (central Italy) producing vast damage in the L'Aquila town and surroundings. In this paper we present the location and geometry of the fault system as obtained by the analysis of main shock and aftershocks recorded by permanent and temporary networks. The distribution of aftershocks, 712 selected events with M L ! 2.3 and 20 with M L ! 4.0, defines a complex, 40 km long, NW trending extensional structure. The main shock fault segment extends for 15-18 km and dips at 45°to the SW, between 10 and 2 km depth. The extent of aftershocks coincides with the surface trace of the Paganica fault, a poorly known normal fault that, after the event, has been quoted to accommodate the extension of the area. We observe a migration of seismicity to the north on an echelon fault that can rupture in future large earthquakes.

[1] We present an updated present-day stress data compilation for the Italian region and discuss it with respect to the geodynamic setting and the seismicity of the area. We collected and analyzed 190 new stress data from borehole breakouts, seismicity, and active faults and checked in detail the previous compilation . Our improved data set consists of 542 data, 362 of which with a reliable quality for stress maps. The Italian region is well sampled, allowing the computation of constrained smoothed stress maps; for surrounding regions we added the World Stress Map 2003 release data. These maps depict the active stress conditions and, in the areas where the data are sparse, contribute to understand the relationship between active stress, past tectonic setting, and the seismicity of the study region. The new data are particularly representative along the northern Apennine front, from the Po Plain to offshore the Adriatic, and along the southern Tyrrhenian Sea, north of Sicily, where they point out a compressive tectonic regime. In the Alps both compressive and transcurrent regimes are observed. Our data also confirm that the whole Apenninic belt and the Calabrian arc are extending. Along the central Adriatic coast, changes from one stress regime to another are shown by abrupt variations in the minimum horizontal stress directions. Other gentler stress rotations, as, for instance, from the southern Apennines to the Calabrian arc or along the northern Apennines, follow the curvature of the arcs and are not associated to a stress regime variation.

No abstract

[1] This paper presents a velocity model of the Italian (central Mediterranean) lithosphere in unprecedented detail. The model is derived by inverting a set of 166,000 P g and P n seismic wave arrival times, restricted to the highest-quality data available. The tomographic images reveal the geometry of the subduction-collision system between the European, Adriatic, and Tyrrhenian plates, over a larger volume and with finer resolution than previous studies. We find two arcs of low-V p anomalies running along the Alps and the Apennines, describing the collision zones of underthrusting continental lithospheres. Our results suggest that in the Apennines, a significant portion of the crust has been subducted below the mountain belt. From the velocity model we can also infer thermal softening of the crustal wedge above the subducting Adriatic plate. In the Tyrrhenian back-arc region, strong and extensive low-V p anomalies depict upwelling asthenospheric material. The tomographic images also allow us to trace the boundary between the Adriatic and the Tyrrhenian plates at Moho depth, revealing some tears in the Adriatic-Ionian subducting lithosphere. The complex lithospheric structure described by this study is the result of a long evolution; the heterogeneities of continental margins, lithospheric underthrusting, and plate indentation have led to subduction variations, slab tears, and asthenospheric upwelling at the present day. The high-resolution model provided here greatly improves our understanding of the central Mediterranean's structural puzzle. The results of this study can also shed light on the evolution of other regions experiencing both oceanic and continental subduction.Citation: Di Stefano, R., E. Kissling, C. Chiarabba, A. Amato, and D. Giardini (2009), Shallow subduction beneath Italy: Three-dimensional images of the Adriatic-European-Tyrrhenian lithosphere system based on high-quality P wave arrival times,

Abstract. We present a new map of the present-day stress field in Italy obtained from all the available data. The map reports 200 horizontal stress directions inferred from 109 borehole breakout data, 44 centroid moment tensor solutions, 34 other focal mechanisms, most of which are from polarity distributions, seven stress inversions of microearthquake data, two averages of T and P axes of earthquake focal mechanisms in zones of diffuse seismic activity, and four fault slip data. The integration of breakout data, which yield horizontal stress directions, with fault plane solutions, which reflect the stress regime, allows us to obtain an improved map of the present-day stress in Italy. This stress field map can be used for a better comprehension of active tectonic processes, for seismic hazard assessment, and to foresee the behavior of faults recognized with other methods. Stress directions obtained from different data, although relative to different depth intervals (e.g., 0-7 km for breakouts and 0-20 km for most of the earthquakes) and to different tectonic units, are consistent. Since many regions in Italy are characterized by an extensional stress regime, we report the minimum horizontal stress (•hmin) orientations. The map shows that an extensional regime affects most of the Apenninic belt. Conversely, a compressional (or transpressional) regime characterizes the eastern Alps, the eastern side of the northern Apennines, and the southern Tyrrhenian to northern Sicily zone. An abrupt change in stress directions marks the transition between northern and southern Apennines, suggesting that the two arcs are characterized by a different tectonic setting and recent evolution. In this paper we report all the data analyzed to date, with their geographic coordinates and average stress directions, and we describe the main stress provinces in Italy in the framework of the tectonic evolution of the region.