Italian accelerometric archive: geological, geophysical and geotechnical investigations at strong-motion stations

Geological, geophysical and geotechnical investigations, for the characterization of the strong-motion recording sites managed by the Italian Civil Protection, have been carried out in the framework of the project “Italian strong-motion database in the period 1972–2004”. The project aimed at creating an updated database of strong-motion data acquired in Italy by different institutions in the time span 1972–2004, and at improving the quality of disseminated data. This article illustrates the state of the recording site characterization before the beginning of the project, explains the criteria adopted to select the sites where geophysical/geotechnical investigation have been performed and describes the results of the promoted field surveys.     

Sources and chronology of fifteen elements in the sediments of lakes affected by metal deposition in a mining area

Sources and chronologies of metal contamination were studied in sediment cores of three lakes of the Rouyn-Noranda mining area (Québec, Canada) affected by atmospheric deposition of anthropogenic contaminants. One of the three lakes also received acid mine drainage. The sediments were dated using ²¹⁰Pb and ¹³⁷Cs and analysed for stable Pb isotope ratios and for total concentrations of 15 elements (Ag, Al, Au, Ca, Cu, Cd, Fe, Hg, Mn, Ni, P, Pb, S, Ti, Zn). Stable lead isotopic signatures helped to determine the quantitative contributions of different industrial Pb sources to our sampling sites. This source apportionment showed the dominant influence of the Rouyn-Noranda copper smelter in airborne Pb emissions for the decades following 1926, when industrialization began in the region. The smelter source had a low ratio of ²⁰⁶Pb/²⁰⁷Pb ranging between 0.90 and 1.05, as typical of the Abitibi Archean sulphides. The relationships between element (metal) sedimentary fluxes and anthropogenic Pb fluxes allowed us to infer the origin of the anthropogenic source. These relationships strongly suggest that the copper smelter was (and may still be) an atmospheric source of Cd, Cu, Pb, Zn, Ag and Hg to the surrounding lakes. Our study indicates that the efforts made by the Rouyn-Noranda copper smelter to reduce airborne emissions of metals have been translated in reduced atmospheric metal loadings to the surrounding lakes.     

Multivariate analysis to investigate Cl distribution in rocks from different settings

Chlorine concentration has been determined by chemical methods in 97 samples of basic rocks collected at Etna volcano (Sicily, Southern Italy), Sao Miguel (Azores Islands), and Lanzarote (Canary Islands). The samples have been processed together with data related to specific magmatic and tectonic conditions, drawn from the literature. Thus, the contents of SiO₂, K₂O, and P₂O₅ of 228 samples have been used to investigate Cl distribution in the considered environments, using principal component analysis. The log-centered variance-covariance matrix has been processed in order to overcome the closure constraints. The results indicate that a clear distinction between continental and oceanic regions can be obtained in the components space. A preliminary discriminant diagram involving chlorine thus can be proposed.     

Organochlorine compounds in tissues of swordfish (Xiphias gladius) from Mediterranean Sea and Azores islands

Polychlorobiphenyls (PCB) and organochlorine (OC) pesticides are endocrine-disrupting chemicals (EDCs). The Italian Ministry of Environment has undertaken a program (1999-2001) to measure levels of contaminants in top marine predators and to develop sensitive biomarkers for the evaluation of toxicological risk in these species. In 1999, 15 swordfishes (Xiphias gladius) taken from the Mediterranean Sea along the Sicilian coast (Strait of Messina, Italy) and in the Atlantic Ocean along the Azores Islands, and analysed for 34 congeners of PCBs and 27 organochlorine (OC) pesticides in gonad, muscle, liver and blubber tissues. In the tissues of Mediterranean swordfishes the sum of the determined PCBs congeners ranged from 4.61 to 4651.17 ng g(-1) on fresh tissue basis. Among organochlorine pesticides DDE, DDT and DDD (TDE) predominated with an overall range of 2.37-4734.56 ng(-1) w.w. In particular p,p'-DDE had concentrations appearing up to 3900 ng(-1), with the highest values found in fatty tissues, such as blubber. In the liver of Azores Island swordfishes lower levels of summation PCBs (8.43-294.17 ng/g w.w.) and summation DDTs (<0.01-217.44 ng/g w.w.) were determined.     

Stellar atmospheres models of K-giant stars: the influence of opacity sources

Four different models for a K-giant atmosphere (T _e=4500K, logg=2) have been computed. Each model is characterized by the inclusion of different opacity sources (H, H^–, (H), metals, blanketing effect, He^–) in order to obtain an evaluation of the model sensitivity concerning the atmospheric structure and the emergent flux. The results show that hydrogen, metals and blanketing effect must be taken into account to achieve self-consistent and reliable models.A picture of the influence of the frequency distribution of the absorption coefficient on the model features is also shown.

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Sommario Sono stati calcolati quattro differenti modelli di una stella gigante K(T _e=4500K, logg=2). Ogni modello è caratterizzato dalla inclusione di differenti sorgenti di opacità (H, H^–, (H), metalli, effetto blanketing, He^–) per ottenere una valutazione della sensibilità del modello per quel che riguarda la struttura atmosferica ed il flusso emergente. I risultati ottenuti mostrano che per costruire modelli auto-consistenti e con un buon grado di affidabilità occorre tener conto almeno delle seguenti sorgenti di opacità: H, metalli, effetto blanketing.Si mostra inoltre come sia possibile una descrizione schematica dell'influenza del coefficiente di assorbimento sulle varie caratteristiche del modello.

     

Out‐of‐plane behaviour of a full scale stone masonry façade. Part 1: specimen and ground motion selection

The out‐of‐plane response of walls in existing stone masonry buildings is one of the major causes of vulnerability commonly observed in post‐earthquake damage surveys. In this context, a shaking table (ST) test campaign was carried out on a full‐scale masonry façade mainly focusing on the characterization of its out‐of‐plane overturning behaviour. The structure tested on the ST is a partial reproduction of an existing building from Azores, damaged during the 9 July 1998 Faial earthquake. The definition of the tested specimen as well as the selection of the input ground motion is reported in this paper. A specific emphasis is given to the definition of the time‐history to be applied during the tests because it was felt as an essential and crucial part of the work to obtain the desired overturning behaviour. The accelerogram to be imposed was selected from a large set of accelerograms (74) by means of a step‐by‐step procedure on the basis of several numerical analyses resorting to the rocking response of rigid blocks. A companion paper (Part 2) focuses on the ST test results and detailed data interpretation. Copyright © 2013 John Wiley & Sons, Ltd.     

Long‐term presence and habitat use of Cuvier's beaked whale (Ziphius cavirostris) in the Central Tyrrhenian Sea

Cuvier's beaked whale (Ziphius cavirostris, G. Cuvier 1823) is a poorly known species and many international agreements have asked for a better understanding of its biology for conservation purposes. In the present study, systematic cetacean surveys were carried out from ferries along a trans‐regional fixed transect in the Central Tyrrhenian Sea (Civitavecchia, Latium – Golfo Aranci, Sardinia), just outside the southeastern border of the Pelagos Sanctuary. This research provided long‐term, consistent data on Cuvier's beaked whale during two research periods (1990–1992 and 2007–2011). The objective of the research was to compare the presence, distribution and habitat use of Cuvier's beaked whale between the two investigated periods. Summer data (June–September) from the two periods were compared in terms of frequency of sightings, group size and spatial distribution related to the main ecogeographical features. A presence‐absence model (generalized additive modelling) was performed to predict habitat suitability in the two study periods. The results highlight long‐term site fidelity of Cuvier's beaked whale in the Central Tyrrhenian Sea with encounter rates comparable to the ones reported for other key areas. Separate suitability models based on 1990s and 2000s data appeared to work for each individual time period but differences were evident between the two periods, indicating changes in habitat selection over time. Our findings of the study appear to expand the definition of suitable beaked whale habitat and underline how the temporal scale of the analysis can affect the results in habitat studies. Moreover, this research highlights the importance of the Central Tyrrhenian Sea marine region for Cuvier's beaked whale and the ability of continuous monitoring to identify changes in cetacean frequency and distribution, necessary for adaptive conservation management approaches.     

A new monitoring station for debris flows in the European Alps: first observations in the Gadria basin

Debris-flow monitoring in instrumented areas is an invaluable way to gather field data that may improve the understanding of these hazardous phenomena. A new experimental site has been equipped in the Autonomous Province of Bozen-Bolzano (Eastern Alps, Italy) for both monitoring purposes and testing early warning systems. The study site (Gadria basin) is a 6.3 km² catchment subjected to frequent debris flows. The monitoring system in the Gadria basin consists of rain gauges, radar sensors, geophones, video cameras, piezometers and soil moisture probes. Transmission of data and alerts from the instruments exploits in part radio technology. The paper presents the data gathered during the first three years of activity, with two debris-flow events recorded at the station varying in magnitude and characteristics, and discusses the perspectives of debris-flow monitoring and related research.     

Hydrological Regime and Renewal Capacity of the Micro-tidal Lesina Lagoon,Italy

A multidisciplinary approach that combines field measurements, artificial neural networks, water balance analyses and hydrodynamic modelling was developed to investigate the water budget and renewal capacity of semi-closed coastal systems. The method was applied to the Lesina Lagoon, a micro-tidal lagoon in the southern Adriatic Sea (Italy). Surface water flux between the lagoon and the sea was determined by neural network prediction and used as input in the analysis. Strong seasonal variations in the water budget equation were predicted. Fresh water inputs estimated by the water balance analysis were used as forcing by a calibrated finite element model to describe the water circulation and transport time scale of the lagoon’s surface waters. The model highlighted the spatial heterogeneity of the renewal behaviour of the system, with a strong east–west water renewal time gradient. Knowledge of spatial distribution of water renewal times is crucial for understanding the lagoon’s renewal capacity and explaining the high spatial variability of the biogeochemistry of the Lesina Lagoon.