Structural features of Panarea volcano in the frame of the Aeolian Arc (Italy): Implications for the 2002–2003 unrest     

Valerio Acocella  Marco Neri  Thomas R. Walter   《Journal of Geodynamics》2009,47(5):288-292

Panarea, characterized by gas unrest in 2002–2003, is the volcanic island with the least constrained structure in the eastern-central Aeolian Arc (Italy). Based on structural measurements, we define here its deformation pattern relative to the Arc. The main deformations are subvertical extension fractures (63% of data), normal faults (25%) and dikes (12%). The mean orientation of the extension fractures and faults is N38°E, with a mean opening direction of N135° ± 8°, implying extension with a moderate component of dextral shear. These data, matched with those available for Stromboli volcano (pure opening) and Vulcano, Lipari and Salina volcanoes (predominant dextral motions) along the eastern-central Arc, suggest a progressive westward rotation of the extension direction and an increase in the dextral shear. The dextral shear turns into compression in the western arc. The recent unrest at Panarea, coeval to that of nearby Stromboli, may also be explained by the structural context, as both volcanoes lie along the portion of the Arc subject to extension.  相似文献   

Reply to comments on “Depth–energy and depth–force relationships in open channel flows II: Analytical findings for power-law cross sections” by A. Valiani,V. Caleffi [Adv. Water Resour. 32 (2009) 213–224]     

Alessandro Valiani  Valerio Caleffi 《Advances in water resources》2009

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Study of site effects in the area of Nocera Umbra (Central Italy) during the 1997 Umbria-Marche seismic sequence     

A. Caserta  F. Bellucci  G. Cultrera  S. Donati  F. Marra  G. Mele  B. Palombo  A. Rovelli 《Journal of Seismology》2000,4(4):555-565

During the M_L = 5.6 and 5.8 earthquakes occurredin central Italy on 26 September 1997 the historiccentre of Nocera Umbra, lying on top of a 120 m highhill, was diffusely damaged (VII-VIII degrees of MCSintensity). Some recently built houses in the modernpart of the town suffered an even higher level ofdamage. A temporary seismic array was deployed toinvestigate a possible correlation between localamplifications of ground motion in this area and theobserved pattern of damage. After a geologic andmacroseismic survey, eight sites were selected asrepresentative of different local conditions, such astopographic irregularities, sharp hard-to-softlithology transitions, alluvium-filled valleys, andboth undisturbed and deformed rocks.Horizontal-to-vertical spectral ratios for bothmicrotremor and earthquake recordings, as well asspectral ratios referred to undisturbed rock sites,were used to quantify local variations of groundmotion. In spite of the diffuse damage in the historiccentre of Nocera Umbra, a small amplification isobserved at the stations on the hill's top. Thissuggests that the higher vulnerability of the ancientbuildings mainly accounts for the diffuse damage inthat part of the town. In the frequency band ofengineering interest (1 to 10 Hz) the largestamplifications of ground motion are found at softsites: in the Topino river valley, where many episodesof severe structural damage occurred, spectralamplification is significant over a broad frequencyband ranging from 2 Hz to more than 20 Hz. Inparticular, in the central part of the valley highamplification (> 4) is found from 3 to 10 Hz,reaching a maximum of 20 around 4 Hz. At the edge ofthe valley, close to the soil-to-rock transition,amplification is as large as 10 in a frequency bandranging from 4 to more than 20 Hz. A significantamplification (by a factor of 10 around 10 Hz) isobserved also at one of the rock sites, possibly dueto the presence of a cataclastic zone related to theactivity of a regional fault that altered themechanical properties of the rock.  相似文献   

The structure of the Campanian Plain and the activity of the Neapolitan volcanoes (Italy)     

Roberto Scandone  Francesca Bellucci  Lucio Lirer  Giuseppe Rolandi 《Journal of Volcanology and Geothermal Research》1991,48(1-2)

The central Campanian Plain is dominated by the structural depression of Acerra whose origin is tectonic, but may have been enlarged and further depressed after the eruption of the Campanian Ignimbrite (42-25 ka). The deposits of the Campanian Ignimbrite are possibly the results of multiple eruptions with huge pyroclastic deposits that covered all the Campanian Plain.The more recent activity of Vesuvius, Campi Flegrei and Procida occurred on the borders of Acerra depression and resulted from a reactivation of regional faults after the Campanian Ignimbrite cycle. The activity of Vesuvius produced the building of a stratovolcano mostly by effusive and plinian explosive eruptions. The Campi Flegrei area, on the contrary, was dominated by the eruption of the Neapolitan Yellow Tuff at 12 ka that produced a caldera collapse of the Gulf of Pozzuoli. The caldera formation controlled the emplacement of the recent activity of Campi Flegrei and the new volcanoes were formed only within the caldera or along its rim.  相似文献   

A new framework for climate sensitivity and prediction: a modelling perspective     

Francesco Ragone  Valerio Lucarini  Frank Lunkeit 《Climate Dynamics》2016,46(5-6):1459-1471

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Horizontal accuracy assessment of very high resolution Google Earth images in the city of Rome,Italy     

Giuseppe Pulighe  Valerio Baiocchi  Flavio Lupia 《International Journal of Digital Earth》2016,9(4):342-362

Google Earth (GE) has recently become the focus of increasing interest and popularity among available online virtual globes used in scientific research projects, due to the free and easily accessed satellite imagery provided with global coverage. Nevertheless, the uses of this service raises several research questions on the quality and uncertainty of spatial data (e.g. positional accuracy, precision, consistency), with implications for potential uses like data collection and validation. This paper aims to analyze the horizontal accuracy of very high resolution (VHR) GE images in the city of Rome (Italy) for the years 2007, 2011, and 2013. The evaluation was conducted by using both Global Positioning System ground truth data and cadastral photogrammetric vertex as independent check points. The validation process includes the comparison of histograms, graph plots, tests of normality, azimuthal direction errors, and the calculation of standard statistical parameters. The results show that GE VHR imageries of Rome have an overall positional accuracy close to 1 m, sufficient for deriving ground truth samples, measurements, and large-scale planimetric maps.  相似文献   

Metal fluxes to the sediments of the northern Venice Lagoon     

Mauro Frignani  Luca G. Bellucci  Leonardo Langone  Herbert Muntau 《Marine Chemistry》1997,58(3-4)

Eighteen short cores were analyzed for major and trace metals (Al, Fe, Ca, Mg, Mn, Si, K, Ti, Pb, Zn, Cu, Ni, Cr), ²¹⁰Pb, ¹³⁷Cs, and other sediment characteristics, so as to describe the chronology of pollution and calculate metal concentration factors and fluxes. Substantial evidence was found that trace metal profiles are influenced by anthropogenic sources and by changes in sediment composition. Only Zn presents concentrations (up to 13.1 μmol g⁻) and concentration factors (1.3 to 13.2) that can be attributed to heavy contamination. Pb, Cu and Ni, in this order, are less significant. The areal distribution of concentrations and inventories reflects the importance of direct sources, in particular the industrial area of Porto Marghera and the Dese river. The inventories of excess metals, above pre-industrial levels, were determined for each core and the three different parts of the study area, the amounts of Zn accumulated in sediments are 11.0 Mmol, 5.1 Mmol and 0.37 Mmol in the Campalto, S. Erasmo, and Palude di Cona areas, respectively. Ruxes were also calculated and compared with those suggested for the atmospheric delivery by Cochran et al. [(1995)b. Atmospheric fluxes of heavy metal contaminants to the Venice Lagoon, Rapp. Comm. Int. Mer Médit., 34, 136.], the atmospheric contribution is predominant or significant in many cases, especially at sites far from the major local inputs. Concentrations and fluxes show a significant increase in the anthropogenic metal supply starting from the second decade of this century, with maximum inputs in the period between the (1930)s and the (1970)s. At some stations a decrease in heavy metal contamination of surficial sediments was found and this could be ascribed to a reduced input of pollutants in recent years.  相似文献   

Diel activity and short‐distance movement pattern of the European spiny lobster,Palinurus elephas,acoustically tracked          下载免费PDF全文

Vincenzo M. Giacalone  Alberto Barausse  Michele Gristina  Carlo Pipitone  Valerio Visconti  Fabio Badalamenti  Giovanni D'Anna 《Marine Ecology》2015,36(3):389-399

This paper presents the results of the application of an ultrasonic telemetry system to the investigation of short‐term movements in the European spiny lobster, Palinurus elephas, in a coastal area of NW Sicily (Central Mediterranean Sea). Ten lobsters were tagged with miniaturized transmitters and released over a favourable habitat and their movements then recorded by means of nine automated receivers with the objective of investigating post‐release displacement, home‐range extension, movement patterns, activity rhythm and the influence of lunar light intensity on lobster activity. Acoustic detection data were used to assess activity and home range using estimates of horizontal and vertical movements and minimum convex polygons, respectively. Continuous wavelet transform (CWT) analysis was applied to time series of position data. Acoustic data from five of 10 lobsters were successfully recorded across a 78‐day study period between April and June 2008. All of them displayed an activity pattern characterized by diurnal sheltering and nocturnal foraging, with higher activity (i.e., longer distances travelled) at night. Their home range measured between 1629 and 8641 m², and all lobsters relocated every 4.6 days on average, probably in search of unexploited feeding grounds. For this reason we hypothesize a nomadic movement pattern for our tagged lobsters. CWT analyses highlighted a 24‐h periodicity in lobster activity, with higher activity from sunset to sunrise. No clear influence of moon phase on lobster activity was detected.  相似文献   

Titan solar occultation observed by Cassini/VIMS: Gas absorption and constraints on aerosol composition     

A. Bellucci  P. Drossart  P.D. Nicholson  K.H. Baines 《Icarus》2009,201(1):198-149

A solar occultation by Titan's atmosphere has been observed through the solar port of the Cassini/VIMS instrument on January 15th, 2006. Transmission spectra acquired during solar egress probe the atmosphere in the altitude range 70 to 900 km at the latitude of 71° S. Several molecular absorption bands of CH₄ and CO are visible in these data. A line-by-line radiative transfer calculation in spherical geometry is used to model three methane bands (1.7, 2.3, 3.3 μm) and the CO 4.7 μm band. Above 200 km, the methane 2.3 μm band is well fit with constant mixing ratio between 1.4 and 1.7%, in agreement with in situ and other Cassini measurements. Under 200 km, there are discrepancies between models and observations that are yet fully understood. Under 480 km, the 3.3 μm CH₄ band is mixed with a large and deep additional absorption. It corresponds to the C-H stretching mode of aliphatic hydrocarbon chains attached to large organic molecules. The CO 4.7 μm band is observed in the lower stratosphere (altitudes below 150 km) and is well fit with a model with constant mixing ratio of 33±10 ppm. The continuum level of the observed transmission spectra provides new constraints on the aerosol content of the atmosphere. A model using fractal aggregates and optical properties of tholins produced by Khare et al. [Khare, B.N., Sagan, C., Arakawa, E.T., Suits, F., Callcott, T.A., Williams, M.W., 1984. Icarus 60, 127-137] is developed. Fractal aggregates with more than 1000 spheres of radius 0.05 μm are needed to fit the data. Clear differences in the chemical composition are revealed between tholins and actual haze particles. Extinction and density profiles are also retrieved using an inversion of the continuum values. An exponential increase of the haze number density is observed under 420 km with a typical scale height of 60 km.  相似文献   

Mapping of water frost and ice at low latitudes on Mars     

F.G. Carrozzo  G. Bellucci  E. D’Aversa 《Icarus》2009,203(2):406-420

This paper reports on mapping of water frost and ice on Mars, in the range of latitudes between 30°S and 30°N. The study has been carried out by analysing 2485 orbits acquired during almost one martian year by the Mars Express/OMEGA imaging spectrometer. Water frost/ice is identified by the presence of ∼1.5 μm, ∼2 μm and ∼3.0 μm absorptions. Although the orbits analysed in this study cover all seasons, water frost/ice is observed only near the aphelion seasons, at Ls = 19° and at Ls = 98-150°. Water frost/ice is detected mainly on the southern hemisphere between 15°S and 30°S latitude while it has not been identified within 15°S-15°N. In the northern hemisphere, the water frost/ice detection is complicated by the presence of clouds. Usually, water frost/ice is found in shadowed areas, while in few cases it is exposed to the sunlight. This indicates a clear relationship with the local illumination conditions on the slopes which favour the water frost/ice deposition on the surface when the temperatures are very low. OMEGA observations span from 10 to 17 LT and the frost/ice is detected mainly between 15 and 16 LT, with practically no detection before 13 LT. We think this is due to the fact that the 10-12 LT observations occur at large distances and it is not a local time effect. A thermal model is used to determine the deposition conditions on the sloped surfaces where water frost/ice has been found. There, daily atmospheric saturation does not occur on pole facing 10-25° slopes with current water vapour abundances but only by assuming values greater than 40 pr μm. Moreover, the water frost/ice is not detected during the northern winter, even if the thermal model foresees daily saturation on 25° slopes.  相似文献