A reappraisal of seismic Q evaluated in Campi Flegrei caldera. Receipt for the application to risk analysis

The civil defense of Italy and the European community have planned to reformulate the volcanic risk in several volcanic areas of Italy, among which Mt. Vesuvius and Campi Flegrei, by taking into account the possible occurrence of damaging pre- or syn-eruptive seismic events. Necessary to achieve this goal is the detailed knowledge of the local attenuation–distance relations. In the present note, we make a survey of the estimates of seismic quality factor (the inverse is proportional to the attenuation coefficient with distance) reported in literature for the area of Campi Flegrei where many, but sometimes contradictory results have been published on this topic. We try to review these results in order to give indications for their correct use when calculating the attenuation laws for this area.     

Improving flow forecasting by error correction modelling in altered catchment conditions

Despite human is an increasingly significant component of the hydrologic cycle in many river basins, most hydrologic models are still developed to accurately reproduce the natural processes and ignore the effect of human activities on the watershed response. This results in non‐stationary model forecast errors and poor predicting performance every time these models are used in non‐pristine watersheds. In the last decade, the representation of human activities in hydrological models has been extensively studied. However, mathematical models integrating the human and the natural dimension are not very common in hydrological applications and nearly unknown in the day‐to‐day practice. In this paper, we propose a new simple data‐driven flow forecast correction method that can be used to simultaneously tackle forecast errors from structural, parameter and input uncertainty, and errors that arise from neglecting human‐induced alterations in conceptual rainfall–runoff models. The correction system is composed of two layers: (i) a classification system that, based on the current flow condition, detects whether the source of error is natural or human induced and (ii) a set of error correction models that are alternatively activated, each tailored to the specific source of errors. As a case study, we consider the highly anthropized Aniene river basin in Italy, where a flow forecasting system is being established to support the operation of a hydropower dam. Results show that, even by using very basic methods, namely if‐then classification rules and linear correction models, the proposed methodology considerably improves the forecasting capability of the original hydrological model. Copyright © 2013 John Wiley & Sons, Ltd.     

Flooding scenarios due to land subsidence and sea‐level rise: a case study for Lipari Island (Italy)

Archaeological and instrumental data indicate that the southern sector of the volcanic island of Lipari has been subsiding for the last 2100 years due to isostatic and tectonic factors, at variable rates of up to ~11 mm a^?1. Based on this data, a detailed marine flooding scenario for 2100 AD is provided for the bay of Marina Lunga in the eastern part of the island from (1) an ultra‐high‐resolution Digital Terrain and Marine Model (DTMM) generated from multibeam bathymetry (MB) and Unmanned Aerial Vehicles (UAV), (2) the rate of land subsidence from Global Positioning System (GPS) data and (3) the regional sea‐level projections of the International Panel on Climate Change (IPCC). When land subsidence is considered, the upper bound of sea‐level rise is estimated at 1.36 m and 1.60 m for RCP4.5 and RCP8.5 climate change scenarios, respectively. Here, we show the expected impact of marine flooding at Lipari for the next 85 years and discuss the hazard implications for the population living along the shore.     

Seismic soil–structure interaction in multi‐span bridges: Application to a railway bridge

The effects of soil‐structure interaction on the seismic response of multi‐span bridges are investigated by means of a modelling strategy based on the domain decomposition technique. First, the analysis methodology is presented: kinematic interaction analysis is performed in the frequency domain by means of a procedure accounting for radiation damping, soil–pile and pile‐to‐pile interaction; the seismic response of the superstructure is evaluated in the time domain by means of user‐friendly finite element programs introducing suitable lumped parameter models take into account the frequency‐dependent impedances of the soil–foundation system. Second, a real multi‐span railway bridge longitudinally restrained at one abutment is analyzed. The input motion is represented by two sets of real accelerograms: one consistent with the Italian seismic code and the other constituted by five records characterized by different frequency contents. The seismic response of the compliant‐base model is compared with that obtained from a fixed‐base model. Pile stress resultants due to kinematic and inertial interactions are also evaluated. The application demonstrates the importance of performing a comprehensive analysis of the soil–foundation–structure system in the design process, in order to capture the effects of soil‐structure interaction in each structural element that may be beneficial or detrimental. Copyright © 2011 John Wiley & Sons, Ltd.     

Formation of cordierite-bearing lavas during anatexis in the lower crust beneath Lipari Island (Aeolian arc,Italy)

Cordierite-bearing lavas (CBL;~105 ka) erupted from the Mt. S. Angelo volcano at Lipari (Aeolian arc, Italy) are high-K andesites, displaying a range in the geochemical and isotopic compositions that reflect heterogeneity in the source and/or processes. CBL consist of megacrysts of Ca-plagioclase and clinopyroxene, euhedral crystals of cordierite and garnet, microphenocrysts of orthopyroxene and plagioclase, set in a heterogeneous rhyodacitic-rhyolitic groundmass containing abundant metamorphic and gabbroic xenoliths. New petrographic, chemical and isotopic data indicate formation of CBL by mixing of basaltic-andesitic magmas and high-K peraluminous rhyolitic magmas of anatectic origin and characterize partial melting processes in the lower continental crust of Lipari. Crustal anatectic melts generated through two main dehydration-melting peritectic reactions of metasedimentary rocks: (1) Biotite + Aluminosilicate + Quartz + Albite = Garnet + Cordierite + K-feldspar + Melt; (2) Biotite + Garnet + Quartz = Orthopyroxene + Cordierite + K-feldspar + Melt. Their position into the petrogenetic grid suggests that heating and consequent melting of metasedimentary rocks occurred at temperatures of 725 < T < 900°C and pressures of 0.4–0.45 GPa. Anatexis in the lower crust of Lipari was induced by protracted emplacement of basic magmas in the lower crust (~130 Ky). Crustal melting of the lower crust at 105 ka affected the volcano evolution, impeding frequent mafic-magma eruptions, and promoting magma stagnation and fractional crystallization processes.     

Managing invasive crayfish: is there a hope?

Given that the impact exerted by non-indigenous crayfish species (NICS) is most often severe, can occur across many levels of ecological organization, and results in the loss of native crayfish populations, the Convention on Biological Diversity approach, as complemented by the European Strategy, is viewed as an excellent framework to be followed to prevent the introduction of NICS and to alleviate or eliminate the damage they inflict. Much effort should be directed to minimize the risks of intentional introductions, as in part done by the Council Regulation No. 708/07 in force in the European Union since 2009. However, this and other regulations are not well harmonized, for instance, with those concerning both the aquarium trade and the harvest of crayfish for human consumption. To make prevention more difficult, there are many records of illegal release of NICS into the wild and of their accidental introduction as undetected contaminants in batches of regulated fish species. As a consequence, it seems necessary that post-introduction mitigation and remediation protocols and processes, such as contingency plans, are always in place to enable rapid detection and early response in order to minimize and, ideally, annul the threats posed by NICS. The aim of this review paper is to offer a synthetic view of the different methods (mechanical removal, physical methods, biological control, biocides, and autocidal methods) proposed and adopted until now to control NICS with a discussion of their pitfalls and potentialities. A glimpse to the ongoing research in the matter will be also given.     

Foreword to the special issue on the ITACA strong motion database

The Special Issue of the Bulletin of Earthquake Engineering devoted to the new Italian strong motion database ITACA (ITalian ACelerometric Archive) is introduced in this foreword. An overview of the papers published in this issue is presented, providing an idea of the number of problems encountered in the compilation of a database as rich of information as ITACA, of the solutions adopted and of the possible research and practical applications. Most of the contents, though specifically addressed to ITACA and to its accelerograms, can be usefully thought of as an exemplification of approaches and methods that can be used for, and extended to, similar databases in other countries.     

On the behavior of mud floc size distribution: model calibration and model behavior

In this paper, we study a population balance equation (PBE) where flocs are distributed into classes according to their mass. Each class i contains i primary particles with mass m _p and size L _p. All differently sized flocs can aggregate, binary breakup into two equally sized flocs is used, and the floc??s fractal dimension is d ₀?=?2, independently of their size. The collision efficiency is kept constant, and the collision frequency derived by Saffman and Turner (J Fluid Mech 1:16?C30, 1956) is used. For the breakup rate, the formulation by Winterwerp (J Hydraul Eng Res 36(3):309?C326, 1998), which accounts for the porosity of flocs, is used. We show that the mean floc size computed with the PBE varies with the shear rate as the Kolmogorov microscale, as observed both in laboratory and in situ. Moreover, the equilibrium mean floc size varies linearly with a global parameter P which is proportional to the ratio between the rates of aggregation and breakup. The ratio between the parameters of aggregation and breakup can therefore be estimated analytically from the observed equilibrium floc size. The parameter for aggregation can be calibrated from the temporal evolution of the mean floc size. We calibrate the PBE model using mixing jar flocculation experiments, see Mietta et al. (J Colloid Interface Sci 336(1):134?C141, 2009a, Ocean Dyn 59:751?C763, 2009b) for details. We show that this model can reproduce the experimental data fairly accurately. The collision efficiency ?? and the ratio between parameters for aggregation and breakup ?? and E are shown to decrease linearly with increasing absolute value of the ??-potential, both for mud and kaolinite suspensions. Suspensions at high pH and different dissolved salt type and concentration have been used. We show that the temporal evolution of the floc size distribution computed with this PBE is very similar to that computed with the PBE developed by Verney et al. (Cont Shelf Res, 2010) where classes are distributed following a geometrical series and mass conservation is statistically ensured. The same terms for aggregation and breakup are used in the two PBEs. Moreover, we argue, using both PBEs, that bimodal distributions become monomodal in a closed system with homogeneous sediment, even when a variable shear rate is applied.     

Identification of the base of the lower-to-middle Campanian Globotruncana ventricosa Zone: Comments on reliability and global correlations

The reliability of the first appearance datum of Globotruncana ventricosa as biozonal marker for the Campanian is discussed. The taxonomy and species concept of G. ventricosa and of Globotruncana tricarinata, that has been either regarded as junior synonym of Globotruncana linneiana or of G. ventricosa, are examined to avoid misidentifications, and one species is here formally described as new, Globotruncana neotricarinata nov. sp. The tropical and subtropical planktic foraminiferal assemblages from the Bottaccione section (Gubbio, Italy), from Deep Sea Drillig Project (DSDP) Site 146 (Caribbean Sea, central Atlantic Ocean), and from Ocean Drilling Program (ODP) Hole 1210B (Shatsky Rise, northwestern Pacific Ocean) are analyzed for the presence of biostratigraphic markers. Lowest and highest occurrence data have been checked in thin sections and washed residues in the Bottaccione section. The comparative biostratigraphic analysis of the planktic foraminiferal distribution highlights: 1) the absence of G. ventricosa at the stratigraphic level at which it is supposed to first occur in the Tethyan area, 2) the presence of transitional specimens resembling G. ventricosa and thus erroneously used to identify the base of the G. ventricosa Zone, 3) the presence of a good sequence of bioevents that appear to be promising for regional and global correlations such as the appearance of Globotruncanita atlantica, Contusotruncana plummerae and the disappearance of Hendersonites carinatus. The correlation potential of these bioevents has been verified across latitudes by studying the Campanian planktic foraminiferal assemblage in pelagic sediments drilled on coastal Tanzania (western Indian Ocean), and at the deep-sea ODP Hole 762C (Exmouth Plateau, western Indian Ocean), that were located at 30°S and 47°S in the Late Cretaceous, respectively. Besides the known diachronous first appearance of G. ventricosa in the Southern Ocean sites, results confirm the difficulty in using G. ventricosa as zonal marker in the tropical and subtropical areas, and the validity of the first appearance datum of C. plummerae for regional and global correlations.