Physics and Seismic Modeling for Monitoring CO<Subscript>2</Subscript> Storage     

José?M.?CarcioneEmail author  Stefano?Picotti  Davide?Gei  Giuliana?Rossi 《Pure and Applied Geophysics》2006,163(1):175-207

We present a new petro-elastical and numerical-simulation methodology to compute synthetic seismograms for reservoirs subject to CO₂ sequestration. The petro-elastical equations model the seismic properties of reservoir rocks saturated with CO₂, methane, oil and brine. The gas properties are obtained from the van der Waals equation and we take into account the absorption of gas by oil and brine, as a function of the in situ pore pressure and temperature. The dry-rock bulk and shear moduli can be obtained either by calibration from real data or by using rock-physics models based on the Hertz-Mindlin and Hashin-Shtrikman theories. Mesoscopic attenuation due to fluids effects is quantified by using White's model of patchy saturation, and the wet-rock velocities are calculated with Gassmann equations by using an effective fluid modulus to describe the velocities predicted by White's model. The simulations are performed with a poro-viscoelastic modeling code based on Biot's theory, where viscoelasticity is described by generalizing the solid/fluid coupling modulus to a relaxation function. Using the pseudo-spectral method, which allows general material variability, a complete and accurate characterization of the reservoir can be obtained. A simulation, that considers the Utsira sand of the North Sea, illustrates the methodology.  相似文献   

Evidence for Mg-rich carbonates on Mars from a 3.9 μm absorption feature     

Ernesto Palomba  Angelo Zinzi  Edward A. Cloutis  Davide Grassi 《Icarus》2009,203(1):58-6003

The origin and nature of the early atmosphere of Mars is still debated. The discovery of sulfate deposits on the surface, coupled with the evidence that there are not large abundances of carbonates detectable on Mars in the optically accessible part of the regolith, leaves open different paleoclimatic evolutionary pathways. Even if carbonates are responsible for the feature observed by TES and Mini-TES at 6.76 μm, alternative hypotheses suggest that it could be due to the presence of Hydrated Iron Sulfates (HIS). Carbonates can be discerned from HIS by investigating the spectral region in which a strong overtone carbonate band is present. The Planetary Fourier Spectrometer on board the Mars Express spacecraft has acquired several thousand martian spectra in the range 1.2-45 μm since January 2004, most of which show a weak absorption feature between 3.8 and 4 μm. A similar feature was observed previously from the Earth, but its origin could not be straightforwardly ascribed to surface materials, and specifically to carbonates. Here we show the surficial nature of this band that can be ascribed to carbonate mixed with the martian soil materials. The materials that best reproduce the detected feature are Mg-rich carbonates (huntite [CaMg₃(CO₃)₄] and/or magnesite [MgCO₃]). The presence of carbonates is demonstrated in both bright and dark martian regions. An evaluation of the likeliest abundance gives an upper limit of ∼10 wt%. The widespread distribution of carbonates supports scenarios that suggest carbonate formation occurred not by precipitation in a water-rich environment but by weathering processes.  相似文献   

Constraints on primordial non-Gaussianity from a needlet analysis of the WMAP-5 data     

Davide Pietrobon  Paolo Cabella  Amedeo Balbi  Giancarlo de Gasperis  Nicola Vittorio 《Monthly notices of the Royal Astronomical Society》2009,396(3):1682-1688

We look for a non-Gaussian signal in the Wilkinson Microwave Anisotropy Probe ( WMAP ) 5-year temperature anisotropy maps by performing a needlet-based data analysis. We use the foreground-reduced maps obtained by the WMAP team through the optimal combination of the W, V and Q channels, and perform realistic non-Gaussian simulations in order to constrain the non-linear coupling parameter f _NL. We apply a third-order estimator of the needlet coefficients skewness and compute the  χ²  statistics of its distribution. We obtain  −80 < f _NL < 120  at 95 per cent confidence level, which is consistent with a Gaussian distribution and comparable to previous constraints on the non-linear coupling. We then develop an estimator of f _NL based on the same simulations and we find consistent constraints on primordial non-Gaussianity. We finally compute the three-point correlation function in needlet space: the constraints on f _NL improve to  −50 < f _NL < 110  at 95 per cent confidence level.  相似文献   

The DRASTIC-Sg model: an extension to the DRASTIC approach for mapping groundwater vulnerability in aquifers subject to differential land subsidence,with application to Mexico City   总被引：1，自引：1，他引：0  

Antonio Hernández-Espriú  J. Antonio Reyna-Gutiérrez  Emilio Sánchez-León  Enrique Cabral-Cano  Jaime Carrera-Hernández  Pedro Martínez-Santos  Sergio Macías-Medrano  Giacomo Falorni  Davide Colombo 《Hydrogeology Journal》2014,22(6):1469-1485

Mexico City relies on groundwater for most of its domestic supply. Over the years, intensive pumping has led to significant drawdowns and, subsequently, to severe land subsidence. Tensile cracks have also developed or reactivated as a result. All such processes cause damage to urban infrastructure, increasing the risk of spills and favoring contaminant propagation into the aquifer. The effects of ground deformation are frequently ignored in groundwater vulnerability studies, but can be relevant in subsiding cities. This report presents an extension to the DRASTIC methodology, named DRASTIC-Sg, which focuses on evaluating groundwater vulnerability in urban aquifers affected by differential subsidence. A subsidence parameter is developed to represent the ground deformation gradient (Sg), and then used to depict areas where damage risk to urban infrastructure is higher due to fracture propagation. Space-geodetic SqueeSAR data and global positioning system (GPS) validation were used to evaluate subsidence rates and gradients, integrating hydrogeological and geomechanical variables into a GIS environment. Results show that classic DRASTIC approaches may underestimate groundwater vulnerability in settings such as the one at hand. Hence, it is concluded that the Sg parameter is a welcome contribution to develop reliable vulnerability assessments in subsiding basins.  相似文献   

Separating polarized cosmological and galactic emissions for cosmic microwave background B-mode polarization experiments     

Federico Stivoli  Carlo Baccigalupi  Davide Maino  Radek Stompor 《Monthly notices of the Royal Astronomical Society》2006,372(2):615-629

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Afterglow light curves, viewing angle and the jet structure of γ-ray bursts     

Elena Rossi  Davide Lazzati  Martin J. Rees 《Monthly notices of the Royal Astronomical Society》2002,332(4):945-950

Gamma-ray bursts are often modelled as jet-like outflows directed towards the observer; the cone angle of the jet is then commonly inferred from the time at which there is a steepening in the power-law decay of the afterglow. We consider an alternative model in which the jet has a beam pattern where the luminosity per unit solid angle (and perhaps also the initial Lorentz factor) decreases smoothly away from the axis, rather than having a well-defined cone angle within which the flow is uniform. We show that the break in the afterglow light curve then occurs at a time that depends on the viewing angle. Instead of implying a range of intrinsically different jets – some very narrow, and others with a similar power spread over a wider cone – the data on afterglow breaks could be consistent with a standardized jet, viewed from different angles. We discuss the implication of this model for the luminosity function.  相似文献   

Time-dependent photoionization in a dusty medium – III. The effect of dust on the photoionization of metals     

Davide Lazzati  Rosalba Perna 《Monthly notices of the Royal Astronomical Society》2003,340(2):694-704

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Data-driven decision management of urban underground infrastructure through groundwater-level time-series cluster analysis: the case of Milan (Italy)     

Sartirana  Davide  Rotiroti  Marco  Bonomi  Tullia  De Amicis  Mattia  Nava  Veronica  Fumagalli  Letizia  Zanotti  Chiara 《Hydrogeology Journal》2022,30(4):1157-1177

Hydrogeology Journal - The significant increase in urbanization has resulted in greater use of the subsurface in urban planning and, therefore, increased interaction between groundwater and...  相似文献   

Spatial and morphometric relationships of submarine landslides offshore west and southwest Iberia     

Gamboa  Davide  Omira  Rachid  Terrinha  Pedro 《Landslides》2022,19(2):387-405

Landslides - Submarine landslides are a ubiquitous geohazard in the marine environment and occur at multiple scales. Increasing efforts have been made during the last decade to catalogue and...  相似文献   

The Campo Imperatore Near Earth Object Survey (CINEOS)     

Andrea Boattini  Germano D’Abramo  Giovanni B. Valsecchi  Andrea Carusi  Andrea Di Paola  Fabrizio Bernardi  Robert Jedicke  Alan W. Harris  Elisabetta Dotto  Fiore De Luise  Davide Perna  Riccardo Leoni 《Earth, Moon, and Planets》2007,100(3-4):259-271

The Campo Imperatore Near Earth Object Survey (CINEOS) is an Italian survey dedicated to the search and follow-up of Near Earth Objects (NEOs). It is operated with the 90 cm f/3 Schmidt telescope at the Campo Imperatore of the Rome Astronomical Observatory (INAF-OAR) as a joint project with the Istituto di Astrofisica Spaziale and Fisica Cosmica (INAF-IASF) in Rome. Since the end of 2001 CINEOS has covered about 4,250 sq. deg to 20th magnitude in the course of about 160 nights. This effort led to the discovery of 7 Near Earth Asteroids (NEAs), 1 comet (167P/CINEOS; a member of the Centaur group) and a few other unusual objects including 2004 XH₅₀ with a unique comet-like orbit. CINEOS has also contributed almost 2,200 preliminary designations and over 30,000 detections to the Minor Planet Center. About 20% of the survey effort was carried out at low solar elongations (LSE), although no object with an orbit interior (Inner Earth Objects, IEO class) or nearly interior to the Earth (Aten class) was found. The work at LSE was, however, very important to test survey strategies implemented with larger telescopes. We also provide the results of a CINEOS simulation on a reliable NEO population model based on the results of two larger scale surveys, Spacewatch and LINEAR.  相似文献