Evaluation of lindane diffusion along the southeastern Adriatic coastal strip (Mediterranean Sea): a case study in an Albanian industrial area

This study aimed to analyze the impact at sea of a pesticide factory located 7 km north of Durres (Albania) by investigating a lowland area under the sea situated 0.7 km from the shoreline. The main product of this factory was lindane. Production ceased in 1991 during the Albanian civil war, and a large amount of industrial waste was dispersed over the ground surrounding the factory, resulting in a high level of lindane pollution. A water-scoop channels the ground water accumulated around the disused factory directly into the sea. The concentrations of lindane in sediments collected along the coasts of the region ranged from 0.60 to 22.55 ng g(-1). The average concentration in the muscles of fish did not exceed the limits specified by European Commission legislation, whereas the concentration in the liver did exceed these limits; consequently, liver is not recommended for consumption.     

Land subsidence along the Ionian coast of SE Sicily (Italy), detection and analysis via Small Baseline Subset (SBAS) multitemporal differential SAR interferometry

The paper presents the results of a multi‐temporal, differential interferometric synthetic aperture radar (DInSAR) analysis aiming to identify active surface deformation phenomena in south‐eastern Sicily. The study area has been chosen because of its strong seismicity, high concentration of industrial and agricultural activities, and high density of people living in the coastal area. Furthermore, the morphology, lithology and climatic features of this sector of the Hyblean foreland are suitable for an interferometric analysis, providing a high coherence over the area. The Small BAseline Subset (SBAS) multitemporal DInSAR technique was used to calculate mean ground velocity maps and displacement time series from a large data set of European Remote Sensing Satellites (ERS 1–2) images spanning the time period 1992–2000. The reliability of the DInSAR results was tested calculating the East_SAR and Up_SAR values over two permanent global positioning system (GPS) stations in the area, and comparing them with the East_GPS and Up_GPS values. The residuals between GPS and DInSAR velocities were 1 and 0.6 mm/yr for the Up and East components, respectively. Four main subsiding areas, previously undetected, have been identified, corresponding with the towns of Augusta, Siracusa, Priolo, and Villasmundo. The observed deformation phenomena are located within coastal structural basins, filled with Pleistocene and Holocence deposits, except the Villasmundo land subsidence, which is located on the Hyblean plateau. The measured deformation rates reach values up to ?18 mm/yr in Augusta, –6 mm/yr in Siracusa, –5 mm/yr in Villasmundo and ?4.5 mm/yr in Priolo. The examination of velocity profiles, time series, and geological data allows us to relate all the detected deformation patterns primarily to groundwater over‐exploitation. A multi‐dimensional interpolation with kriging was performed to obtain a field subsidence map. A first‐order elastic deformation model was used to simulate the peculiar features of the Villasmundo subsidence. Copyright © 2011 John Wiley & Sons, Ltd.     

Complexity in Sequences of Solar Flares and Earthquakes

In this paper the statistical properties of solar flares and earthquakes are compared by analyzing the energy distributions, the time series of energies and interevent times, and, above all, the distributions of interevent times per se. It is shown that the two phenomena have different statistics of scaling, and even the same phenomenon, when observed in different periods or at different locations, is characterized by different statistics that cannot be uniformly rescaled onto a single, universal curve. The results indicate apparent complexity of impulsive energy release processes, which neither follow a common behaviour nor could be attributed to a universal physical mechanism.     

The rate of sedimentation from turbulent suspension: An experimental model with application to pyroclastic density currents and discussion on the grain‐size dependence of flow runout

Large‐scale experiments generating ground‐hugging multiphase flows were carried out with the aim of modelling the rate of sedimentation, of pyroclastic density currents. The current was initiated by the impact on the ground of a dense gas‐particle fountain issuing from a vertical conduit. On impact, a thick massive deposit was formed. The grain size of the massive deposit was almost identical to that of the mixture feeding the fountain, suggesting that similar layers formed at the impact of a natural volcanic fountain should be representative of the parent grain‐size distribution of the eruption. The flow evolved laterally into a turbulent suspension current that sedimented a thin, tractive layer. A good correlation was found between the ratio of transported/sedimented load and the normalized Rouse number of the turbulent current. A model of the sedimentation rate was developed, which shows a relationship between grain size and flow runout. A current fed with coarser particles has a higher sedimentation rate, a larger grain‐size selectivity and runs shorter than a current fed with finer particles. Application of the model to pyroclastic deposits of Vesuvius and Campi Flegrei of Southern Italy resulted in sedimentation rates falling inside the range of experiments and allowed definition of the duration of pyroclastic density currents which add important information on the hazard of such dangerous flows. The model could possibly be extended, in the future, to other geological density currents as, for example, turbidity currents.     

Vegetation heterogeneity in Monte Desert ecosystems: A multi-scale approach linking patterns and processes

We review the current state of research on vegetation heterogeneity in the Monte Desert at scales varying from landscape to intra-patch. Different factors are related to vegetation heterogeneity at every scale. At a coarse scale (i.e. landscapes and communities) vegetation heterogeneity is commonly determined by abiotic factors, whereas biotic interactions usually influence fine scale (patch, intrapatch) heterogeneity. Communities are distributed at the landscape scale according to differences in precipitation, topography and soil attributes. On the other hand, there is evidence that the spatial pattern of plant patches within communities is determined by runon –runoff processes, although biotic influences such as grazing can induce changes in the spatial pattern of patches when plant cover is strongly reduced. In the same way, at patch and intrapatch scales, biotic interactions (i.e. plant –plant interactions, grazing) determine the size and the species composition of plant patches as well as the distribution of species inside plant patches. However, the mechanisms operating behind such biotic interactions at small scales are commonly related to plant-induced changes in the physical environment. We also found evidence of cross-scale interactions, feedbacks, and non-linear effects such as those induced by grazing disturbance. Our analysis showed some regional differences in patterns and processes related to vegetation heterogeneity along the Monte Desert which can be ascribed to climatic and taxonomic variation among areas. Although information about vegetation heterogeneity and its causes and consequences in the Monte Desert is abundant, some areas where knowledge is scarce are detailed.     

Small‐scale experimental simulation of talus evolution

We investigated a small‐scale laboratory model of a talus slope evolution. Five different size classes of basaltic rock were selected and marked with different colours. Homogenized mixtures of grains of different sizes were dropped from a fixed height onto a tilted experimental board covered with a loose granular layer. This was conducted in a series of regular sequences, and the resulting distribution on the board was studied after each sequence. At the beginning of the experiment, the grains developed a longitudinal gradation similar to natural talus slopes, where small grains settle at the top while the large ones roll down to the distal part. However, after a transient period dominated by single‐particle dynamics on the inert granular medium, the evolution proved to be more variable than expected. Due to the continuous shower of falling grains, the shear stress at the bottom of the upper granular layer increased. This resulted initially in a slow creep down slope that finally collapsed in large avalanches homogenizing the material. The slides occurred at the boundary between a weaker layer created by migration of small grains through the interstices, and marked by a vertical transition between small and large grains. We compare the experimental findings with observations from natural talus slopes, and suggest that similar experiments may be helpful in understanding the evolution of taluses. Copyright © 2009 John Wiley & Sons, Ltd.