A syn-eruptive ground deformation episode measured by GPS,during the 2001 eruption on the upper southern flank of Mt Etna   总被引：4，自引：0，他引：4  

Alessandro?BonforteEmail author  Francesco?Guglielmino  Mimmo?Palano  Giuseppe?Puglisi 《Bulletin of Volcanology》2004,66(4):336-341

Ground deformation occurring on the southern flank of Mt Etna volcano during the July–August 2001 eruption was monitored by GPS measurements along an E–W profile crossing the fissure system. This profile was measured eight times during the eruption, using the 'stop and go' semi-kinematic technique. Horizontal and vertical displacements between GPS surveys are reported for each station. The most significant event is a deformation episode occurring during the first week of the eruption, between 25–27 July. Displacements were measured on benchmarks close to the eruptive fissure and the tensile 1989 fracture. Data inversions for measured displacements were performed using the Okada model. The model shows the narrowing of the 2001 dyke accompanied by a dextral dislocation along an east-dipping fault, parallel to the 1989 fracture.Editorial responsibility: T. Druitt  相似文献   

Fluid circulation and structural discontinuities inside Misti volcano (Peru) inferred from self-potential measurements     

Anthony Finizola  Jean-Franois Lnat  Orlando Macedo  Domingo Ramos  Jean-Claude Thouret  Francesco Sortino 《Journal of Volcanology and Geothermal Research》2004,135(4):216

One of the seven potentially active andesite stratovolcanoes in southern Peru, Misti (5822 m), located 17 km northeast and 3.5 km above Arequipa, represents a major threat to the population (900,000 inhabitants). Our recent geophysical and geochemical research comprises an extensive self-potential (SP) data set, an audio–magnetotelluric (AMT) profile across the volcano and CO₂ concentrations in the soil along a radial profile. The SP survey is the first of its kind in providing a complete mapping of a large andesitic stratovolcano 20 km in diameter. The SP mapping enables us to analyze the SP signature associated with a subduction-related active volcano.The general SP pattern of Misti is similar to that of most volcanoes with a hydrogeologic zone in the lower flanks and a hydrothermal zone in the upper central area. A quasi-systematic relationship exists between SP and elevation. Zones with constant SP/altitude gradients (Ce) are observed in both hydrogeologic (negative Ce) and hydrothermal (positive Ce) zones. Transition zones between the different Ce zones, which form a concentric pattern around the summit, have been interpreted in terms of lateral heterogeneities in the lithology. The highest amplitudes of SP anomalies seem to coincide with highly resistive zones. The hydrothermal system 6 km in diameter, which extends over an area much larger than the summit caldera, may be constrained by an older, concealed collapse caldera. A sealed zone has apparently developed through alteration in the hydrothermal system, blocking the migration of CO₂ upward. Significant CO₂ emanations are thus observed on the lower flanks but are absent above the hydrothermal zone.  相似文献   

High-temperature rapid pyrometamorphism induced by a charcoal pit burning: The case of Ricetto,central Italy     

Flavio?CapitanioEmail author  Francesco?Larocca  Salvatore?Improta 《International Journal of Earth Sciences》2004,93(4):656-656

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The Numidian Sequence between Guelma and Constantine (Eastern Tell,Algeria)*     

E. Moretti  R. Coccioni  F. Guerrera  Jean-Claude Lahondre  Francesco Loiacono  Diego Puglisi 《地学学报》1991,3(2):153-165

The Numidian Sequence represents one of the main tectono-stratigraphic units involved in the geological evolution of the Maghrebian orogen during the Upper Oligocene-Lower Miocene. Geo-structural aqalysis led to the reconstruction of tectonc-stratigraphic units and recognition of two main tectonic phases (Eocene and Lower Miocene). Sedimentological analysis of the studied sections has resulted in the distinction of arenaceous and conglomeratic facies generated by debris flows or high-density turbidity currents on a submarine slope, present within the pelitic-arenaceous and arenaceous-pelitic sequences which also contain slumped units in places. Previous and new micropalaeontological data indicate Late Oligocene-Early Burdigalian ages for the Numidian sequences of the Constantine Mountains. On the basis of petrographic study the Numidian rocks can be classified as poorly sorted quartzarenites containing siliciclastic matrix. The overall petrographic data indicate that the Continental intercalaire (Hoggar, Tassili and Fezzan) and Series Pharusienne (Hoggar and Eglab) are possible supply areas for the Numidian quartz.  相似文献   

XIe assemblée générale de l’Union Géodésique et Géophysique internationale à Toronto,Ontario, Canada 3–14 Septembre 1957     

Secrétaire général de l’association Prof. Francesco Signore 《Bulletin of Volcanology》1958,19(1):3-84

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Der Einfluss der Strömung auf die Verteilung der TrichopterenAgapetus gr.fuscipes Curt. undSilo gr.nigricornis Pict     

Giampaolo Moretti  Francesco Saverio Gianotti 《Aquatic Sciences - Research Across Boundaries》1962,24(2):467-484

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How many predictors in species distribution models at the landscape scale? Land use versus LiDAR-derived canopy height     

Gentile Francesco Ficetola  Anna Bonardi  Caspar A. Mücher  Niels L.M. Gilissen  Emilio Padoa-Schioppa 《International journal of geographical information science》2014,28(8):1723-1739

At the local spatial scale, land-use variables are often employed as predictors for ecological niche models (ENMs). Remote sensing can provide additional synoptic information describing vegetation structure in detail. However, there is limited knowledge on which environmental variables and how many of them should be used to calibrate ENMs. We used an information-theoretic approach to compare the performance of ENMs using different sets of predictors: (1) a full set of land-cover variables (seven, obtained from the LGN6 Dutch National Land Use Database); (2) a reduced set of land-cover variables (three); (3) remotely sensed laser data optimized to measure vegetation structure and canopy height (LiDAR, light detection and ranging); and (4) combinations of land cover and LiDAR. ENMs were built for a set of bird species in the Veluwe Natura 2000 site (the Netherlands); for each species, 26–214 records were available from standardized monitoring. Models were built using MaxEnt, and the best performing models were identified using the Akaike’s information criterion corrected for small sample size (AICc). For 78% of the bird species analysed, LiDAR data were included in the best AICc model. The model including LiDAR only was the best performing one in most cases, followed by the model including a reduced set of land-use variables. Models including many land-use variables tended to have limited support. The number of variables included in the best model increased for species with more presence records. For all species with 33 records or less, the best model included LiDAR only. Models with many land-use variables were only selected for species with >150 records. Test area under the curve (AUC) scores ranged between 0.72 and 0.92. Remote sensing data can thus provide regional information useful for modelling at the local and landscape scale, particularly when presence records are limited. ENMs can be optimized through the selection of the number and identity of environmental predictors. Few variables can be sufficient if presence records are limited in number. Synoptic remote sensing data provide a good measure of vegetation structure and may allow a better representation of the available habitat, being extremely useful in this case. Conversely, a larger number of predictors, including land-use variables, can be useful if a large number of presence records are available.  相似文献   

Long‐term demographic and reproductive trends in Ciona intestinalis sp. A          下载免费PDF全文

Luigi Caputi  Fabio Crocetta  Francesco Toscano  Paolo Sordino  Paola Cirino 《Marine Ecology》2015,36(1):118-128

Ciona intestinalis sp. A (Tunicata, Ascidiacea) is a marine invertebrate with a widespread distribution and high invasive potential, yet little is known about its ecology. Here, the macrodynamics of demographic and reproductive trends were first determined using archive data covering 2002–2012. Species abundance in the central Tyrrhenian Sea (Campania, Italy ‐ NW Mediterranean) displayed Poisson distribution across 2002–2008, massive die‐off in 2009/2010 and population recovery in 2011/2012. We defined the seasonal ranges of sea surface temperature in which sampling size, animal size and reproductive status reached their highest values. In 2003/2004, self and non‐self fertilization appeared to follow reverse trends across the year. The long‐term recording run here on Ciona intestinalis sp. A provides novel insights into its population biology and ecology, and represents a valuable tool for sampling management and research planning.  相似文献   

Probabilistic GIS-based method for delineation of urban flooding risk hotspots   总被引：3，自引：1，他引：2  

Fatemeh Jalayer  Raffaele De Risi  Francesco De Paola  Maurizio Giugni  Gaetano Manfredi  Paolo Gasparini  Maria Elena Topa  Nebyou Yonas  Kumelachew Yeshitela  Alemu Nebebe  Gina Cavan  Sarah Lindley  Andreas Printz  Florian Renner 《Natural Hazards》2014,73(2):975-1001

Identifying urban flooding risk hotspots is one of the first steps in an integrated methodology for urban flood risk assessment and mitigation. This work employs three GIS-based frameworks for identifying urban flooding risk hotspots for residential buildings and urban corridors. This is done by overlaying a map of potentially flood-prone areas [estimated through the topographic wetness index (TWI)], a map of residential areas and urban corridors [extracted from a city-wide assessment of urban morphology types (UMT)], and a geo-spatial census dataset. A maximum likelihood method (MLE) is employed for estimating the threshold used for identifying the flood-prone areas (the TWI threshold) based on the inundation profiles calculated for various return periods within a given spatial window. Furthermore, Bayesian parameter estimation is employed in order to estimate the TWI threshold based on inundation profiles calculated for more than one spatial window. For different statistics of the TWI threshold (e.g. MLE estimate, 16th percentile, 50th percentile), the map of the potentially flood-prone areas is overlaid with the map of urban morphology units, identified as residential and urban corridors, in order to delineate the urban hotspots for both UMT. Moreover, information related to population density is integrated by overlaying geo-spatial census datasets in order to estimate the number of people affected by flooding. Differences in exposure characteristics have been assessed for a range of different residential types. As a demonstration, urban flooding risk hotspots are delineated for different percentiles of the TWI value for the city of Addis Ababa, Ethiopia.  相似文献   

Numerical modelling of centrifuge dynamic tests of circular tunnels in dry sand   总被引：3，自引：2，他引：1  

Riccardo Conti  Giulia M. B. Viggiani  Francesco Perugini 《Acta Geotechnica》2014,9(4):597-612

This paper describes the numerical simulation of two dynamic centrifuge tests on reduced scale models of shallow tunnels in dry sand, carried out using both an advanced bounding surface plasticity constitutive soil model and a simple Mohr–Coulomb elastic-perfectly plastic model with embedded nonlinear and hysteretic behaviour. The predictive capabilities of the two constitutive models are assessed by comparing numerical predictions and experimental data in terms of accelerations at several positions in the model, and bending moment and hoop forces in the lining. Computed and recorded accelerations match well, and a quite good agreement is achieved also in terms of dynamic bending moments in the lining, while numerical and experimental values of the hoop force differ significantly with one another. The influence of the contact assumption between the tunnel and the soil is investigated by comparing the experimental data and the numerical results obtained with different interface conditions with the analytical solutions. The overall performance of the two models is very similar indicating that at least for dry sand, where shear-volumetric coupling is less relevant, even a simple model can provide an adequate representation of soil behaviour under dynamic conditions.  相似文献