Volcanic geomorphology and tectonics of the Aeolian archipelago (Southern Italy) based on integrated DEM data   总被引：1，自引：0，他引：1  

Massimiliano FavalliM  Dávid Karátson  Roberto Mazzuoli  Maria Teresa Pareschi  Guido Ventura 《Bulletin of Volcanology》2005,68(2):157-170

The geomorphological and morphometric analysis of the sea floor topography surrounding the Aeolian Islands, South Tyrrhenian Sea, Italy, provides insights into the relationships between the volcanological evolution of the islands and their tectonic features. We constructed geomorphological maps of the submarine portions of the seven large edifices constituting the islands on the basis of a DEM with a 5 m resolution step. These maps include constructional and destructional landforms such as submarine volcanic vents located west of Lipari and north of Alicudi, and hummocky surfaces recognised north of Lipari and Salina. The latter landforms, together with the occurrence of large scars affecting the main edifices on land, suggest that sector collapses affected some islands. Geomorphological data indicate that the location of subaerial and submarine vents is strongly controlled by local tectonic structures striking WNW-ESE (Alicudi-Filicudi sector), NNW-SSE (Salina-Lipari-Vulcano sector) and NE-SW (Panarea-Stromboli sector). The islands can be divided into two groups on the basis of some morphometric parameters: a first group with a pancake-like shape, Dp/D (abrasion platform diameter/basal diameter) higher than 0.40 and H/D (total height/basal diameter) lower than 0.13, and a second group with a conical shape, characterised by Dp/D lower than 0.34 and H/D higher than 0.14. These ratios and other morphometric parameters reflect the different volcanological and structural evolution of the Aeolian Islands. The pancake-like shaped complexes have been created, in addition to their submarine stage, by extrusive and highly explosive activity, whereas the cone-shaped edifices have been characterised by effusive or moderate explosive activity.Editorial responsibility: C Kilburn  相似文献   

Geochemistry of the Submarine Gaseous Emissions of Panarea (Aeolian Islands, Southern Italy): Magmatic vs. Hydrothermal Origin and Implications for Volcanic Surveillance     

Giovanni Chiodini  Stefano Caliro  Giorgio Caramanna  Domenico Granieri  Carmine Minopoli  Roberto Moretti  Lavinia Perotta  Guido Ventura 《Pure and Applied Geophysics》2006,163(4):759-780

The marine sector surrounding Panarea Island (Aeolian Islands, South Italy) is affected by widespread submarine emissions of CO₂ -rich gases and thermal water discharges which have been known since the Roman Age. On November 3^rd, 2002 an anomalous degassing event affected the area, probably in response to a submarine explosion. The concentrations of minor reactive gases (CO, CH₄ and H₂) of samples collected in November and December, 2002 show drastic compositional changes when compared to previous samples collected from the same area in the 1980s. In particular the samples collected after the November 3^rd phenomenon display relative increases in H₂ and CO and a strong decrease in the CH₄ contents, while other gas species show no significant change. The interaction of the original gas with seawater explains the variable contents of CO₂, H₂S, N₂, Ar and He which characterize the different samples, but cannot explain the large variations of CO, CH₄ and H₂ which are instead compatible with changes in the redox, temperature and pressure conditions of the system. Two models, both implying an increasing input of magmatic fluids are compatible with the observed variations of minor reactive species. In the first one, the input of magmatic fluids drives the hydrothermal system towards atypical (more oxidizing) redox conditions, slowly pressurizing the system up to a critical state. In the second one, the hydrothermal system is flashed by the rising high-T volcanic fluid, suddenly released by a magmatic body at depth. The two models have different implications for volcanic surveillance and risk assessment: In the first case, the November 3^rd event may represent both the culmination of a relatively slow process which caused the overpressurization of the hydrothermal system and the beginning of a new phase of quiescence. The possible evolution of the second model is unforeseeable because it is mainly related to the thermal, baric and compositional state of the deep magmatic system that is poorly known.  相似文献   

Determination of the Physical Parameters of Binary Systems: A Statistical Approach     

Fabrizio Barone  Santi Mancuso  Leopoldo Milano  Guido Russo 《Astrophysics and Space Science》1998,260(4):469-491

  相似文献   

Practical application of fractal analysis: problems and solutions   总被引：2，自引：0，他引：2  

Guido Gonzato  Francesco Mulargia  & Warner Marzocchi 《Geophysical Journal International》1998,132(2):275-282

  相似文献   

A critical appraisal of the Cayconi Formation, Crucero Basin, southeastern Peru     

Hamish A. Sandeman  Alan H. Clark  Edward Farrar  Guido Arroyo-Pauca 《Journal of South American Earth Sciences》1996,9(5-6)

The Cayconi Formation of the Crucero Basin, Puno Department, southeastern Peru, has been described as a 800–1000 m sequence of Oligocene and Miocene fanglomerate and lacustrine sedimentary rocks, interlayered with mafic and silicic volcanic rocks, and unconformably overlying Paleozoic and Cretaceous successions. On the basis of new field and petrological investigations, key aspects of the stratigraphic relationships of the rocks comprising this formation, and hence the viability of this lithostratigraphic name, are questioned. Thus, several sedimentary units previously assigned to the Cayconi Formation are reinterpreted as Cretaceous or older. We further argue that the formational terminology fails to accomodate the great variety of volcanic rocks, which are, moreover, disposed in isolated eruptive fields. We therefore propose establishment of the Crucero Supergroup as a broad, yet flexible framework for lithostratigraphic subdivision of the Tertiary sequences of the Cordillera Oriental of southeastern Peru. This new nomenclature accomodates the voluminous two-mica ash flow tuffs (Macusani Volcanics) and associated rocks of the Quenamari Meseta, a succession excluded from the existing lithostratigraphic classification scheme. It also permits distinction between the petrogenetically-contrasted upper Oligocene — Lower Miocene and Middle Miocene — Upper Miocene volcanic suites, which dominate, respectively, the Picotani and Quenamari Groups comprising the proposed Crucero Supergroup. Finally, the economically important granitic/rhyolitic intrusive centers cogenetic with the volcanic rocks are readily assignable to intrusive lithodemes in each group.  相似文献   

The statistical nature of the upper continental crystalline crust derived from in situ seismic measurements     

Guido Kneib 《Geophysical Journal International》1995,122(2):594-616

  相似文献   

Seasonal and latitudinal distribution of trace gases in the stratosphere: Results from a 2D residual circulation model     

Guido Visconti  Giovanni Pitari 《Journal of Atmospheric Chemistry》1987,5(3):255-289

Results for minor stratospheric constituents using a 2D model with self-consistent transport parameters are reported. The meridional circulation is obtained from the output of the MIT-GIT 3D stratospheric model (Cunnold et al., 1975). Consistent data from the same model are used to evaluate the diffusive tensors following the formalism of Holton (1981) and Tung (1982). Chemical damping is consequently taken into account, so that the entire model is built in a selfconsistent manner at the least with the 3D model and no ad hoc assumptions are made with respect of transport parameters. This version of the model represents a major improvement on previous work (Pitari and Visconti, 1984), which used to much too simple chemistry. Results are compared whenever possible with available experimental data, with particular emphasis on chemical reacting species. This comparison shows in general an agreement which is qualitatively similar to the one obtained from classical Eulerian models where transport parameters are often tuned to long-lived tracers without any sound physical basis.  相似文献   

Generic precursors to coastal earthquakes: Inferences from Denali fault earthquake   总被引：2，自引：0，他引：2  

Ramesh P. Singh  Guido Cervone  Vijay P. Singh  Menas Kafatos 《Tectonophysics》2007,431(1-4):231

Recent research has shown evidence of strong coupling between the atmosphere and lithosphere in coastal regions, associating abnormal atmospheric phenomena to the occurrence of strong earthquakes. Surface latent heat flux (SLHF), total column water vapor (CWV), relative humidity (RH) and total ozone column (TOC), analyzed over the epicentral region of the Denali fault earthquake of November 3, 2002, exhibit anomalous behavior that could be related to the earthquake preparatory process and its occurrence. The complementary nature of the parameters provides strong support that the anomalous values were driven by lithospheric processes, rather than other atmospheric phenomena. Due to the wide availability of remote sensing observations of atmospheric parameters, the detection of anomalies can be used to mitigate the earthquake risks.  相似文献   

Monitoring and predicting channel change in a free‐evolving,small Alpine river: Ridanna Creek (North East Italy)     

Rossella Luchi  Walter Bertoldi  Guido Zolezzi  Marco Tubino 《地球表面变化过程与地形》2007,32(14):2104-2119

The recent (25 years) morphodynamics of a proglacial reach of the Ridanna Creek, North‐East Italy, evolving in the absence of human constraints, has been investigated by means of an intensive field activity and of the analysis of aerial photographs. The study reach mostly displays a braided morphology, with sharp downstream variations of valley gradient, sediment size and formative conditions within the main channel. These discontinuities are associated with different processes of channel adjustment at different timescales, which have been quantified by coupling hydrological with morphological information. Several processes of channel change and variations in braiding intensity have been documented along the whole reach and highlight how a regular, weakly meandering main channel may significantly affect the morphodynamics of the braided network. A first attempt to predict the morphological instability of this main channel at the observed spatial scales through existing linear theories of curved river channels shows a good agreement with field observations. Finally, the complete hydro‐morphodynamical characterization of such an undisturbed alpine river reach can provide a relevant contribution to the definition of reference conditions for Alpine rivers required by the EU Water Framework Directive. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Measuring the fractal dimensions of ideal and actual objects: implications for application in geology and geophysics   总被引：1，自引：0，他引：1  

Guido Gonzato  Francesco Mulargia  & Matteo Ciccotti 《Geophysical Journal International》2000,142(1):108-116

  相似文献