Warp diffusion in accretion discs: a numerical investigation     

Giuseppe Lodato  J. E. Pringle 《Monthly notices of the Royal Astronomical Society》2007,381(3):1287-1300

  相似文献   

An improved model for the formation times of dark matter haloes     

Carlo Giocoli  Jorge Moreno  Ravi K. Sheth  Giuseppe Tormen 《Monthly notices of the Royal Astronomical Society》2007,376(3):977-983

  相似文献   

Intracontinental tectonic melange in Southern Apennines     

Stefano Catalano  Giuseppe Grasso  Paolo Mazzoleni  Carmelo Monaco  Luigi Tortorici 《地学学报》2007,19(4):287-293

On the axial zone of the Southern Apennines the major tectonic boundary between the inner platform (Western platform unit) and the pelagic (Lagonegro units) domains is represented by a thick level of highly deformed rock‐assemblage. Structural analysis reveals that this tectonic unit represents an intracontinental melange complex characterized by a block‐in‐matrix fabric that contains blocks from both hangingwall platform and footwall basin units. This unit comprises different sets of structures that, caused by shearing processes, developed at depths ranging from about 8–9 km to the surface. These tectonites represent the product of a crustal shear zone developed at the major boundary between platform‐basin domains of Adria during the thick‐skinned tectonic processes controlling the Southern Apennines mountain building.  相似文献   

A numerical procedure for predicting rainfall‐induced movements of active landslides along pre‐existing slip surfaces     

Michele Calvello  Leonardo Cascini  Giuseppe Sorbino 《国际地质力学数值与分析法杂志》2008,32(4):327-351

A numerical model to predict landslide movements along pre‐existing slip surfaces from rainfall data is presented. The model comprises: a transient seepage finite‐element analysis to compute the variations of pore water pressures due to rainfall; a limit equilibrium stability analysis to compute the factors of safety along the slip surface associated with transient pore pressure conditions; an empirical relationship between the factor of safety and the rate of displacement of the slide along the slip surface; an optimization algorithm for the calibration of analyses and relationships based on available monitoring data. The model is validated with reference to a well‐monitored active slide in central Italy, characterized by very slow movements occurring within a narrow band of weathered bedrock overlaid by a clayey silt colluvial cover. The model is conveniently divided and presented in two parts: a groundwater model and a kinematic model. In the first part, monthly recorded rainfall data are used as time‐dependent flow boundary conditions of the transient seepage analysis, while piezometric levels are used to calibrate the analysis by minimizing the errors between monitoring data and computed pore pressures. In the second part, measured inclinometric movements are used to calibrate the empirical relationship between the rate of displacement along the slip surface and the factor of safety, whose variation with time is computed by a time‐dependent stability analysis. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

The importance of mergers for the origin of intracluster stars in cosmological simulations of galaxy clusters     

Giuseppe Murante  Martina Giovalli  Ortwin Gerhard  Magda Arnaboldi  Stefano Borgani  Klaus Dolag 《Monthly notices of the Royal Astronomical Society》2007,377(1):2-16

  相似文献   

Measuring the north–south coseismic displacement component with high‐resolution multi‐aperture InSAR          下载免费PDF全文

John Peter Merryman Boncori  Giuseppe Pezzo 《地学学报》2015,27(1):28-35

Earthquake source inversions based on space‐borne Synthetic Aperture Radar interferometry (InSAR) are used extensively. Typically, however, only the line‐of‐sight (LoS) surface displacement component is measured, which is mainly sensitive to the vertical and E–W deformations, although well‐established methods also exist to estimate the flight‐path component, which is highly sensitive to the N–S displacement. With high‐resolution sensors, these techniques are particularly appealing, because accuracies in the order of 3 cm can be achieved, while retaining spatial resolutions between 45 m and a few km, depending on the required level of filtering. We discuss the application to COSMO‐SkyMed SAR imagery of the Spectral Diversity or Multi Aperture Interferometry technique, presenting the first SAR flight‐path displacement field associated with the Mw 6.3, 2009 L'Aquila event (central Apennines). Finally, we observe and characterize a previously unknown misregistration pattern.  相似文献   

Ensemble smoothing of land subsidence measurements for reservoir geomechanical characterization          下载免费PDF全文

Domenico Baù  Massimiliano Ferronato  Giuseppe Gambolati  Pietro Teatini  Ayman Alzraiee 《国际地质力学数值与分析法杂志》2015,39(2):207-228

Geomechanical models are often used to predict the impact on land surface of fluid withdrawal from deep reservoirs, as well as investigating measures for mitigation. The ability to accurately simulate surface displacements, however, is often impaired by limited information on the geomechanical parameters characterizing the geological formations of interest. In this study, we employ an ensemble smoother, a data assimilation algorithm, to provide improved estimates of reservoir parameters through assimilation of measurements of both horizontal and vertical surface displacement into geomechanical model results. The method leverages the demonstrated potential of remote sensing techniques developed in the last decade to provide accurate displacement data for large areas of the land surface. For evaluation purposes, the methodology is applied to the case of a disk‐shaped reservoir embedded in a homogeneous, isotropic, and linearly elastic half space, subject to a uniform change in fluid pressure. Multiple sources of uncertainty are investigated, including the radius, R, the thickness, h, and the depth, c, of the reservoir; the pore pressure change, Δp; porous medium's vertical uniaxial compressibility, c_M, and Poisson's ratio, ν, and the ratio, s, between the compressibilities of the medium during loading and unloading cycles. Results from all simulations show that the ensemble smoother has the capability to effectively reduce the uncertainty associated with those parameters to which the variability and the spatial distribution of land surface displacements are most sensitive, namely, R, c, c_M, and s. These analyses demonstrate that the estimation of these parameters values depends on the number of measurements assimilated and the error assigned to the measurement values. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Core Jamming in Unconsolidated Formations     

Peixoto Filho  Flávio Tito  Vargas Junior  Euripedes do Amaral  Santos  Erick Slis Raggio  Ferreira  Francisco Henriques 《Geotechnical and Geological Engineering》2021,39(6):4127-4142

Geotechnical and Geological Engineering - In coring operations, core jamming is a permanent concern, taking place when the rock core sample becomes stuck within the inner core barrel, thus...  相似文献   

Late Pleistocene to Holocene record of changing uplift rates in southern Calabria and northeastern Sicily (southern Italy, Central Mediterranean Sea)   总被引：3，自引：1，他引：2  

Fabrizio Antonioli  Luigi Ferranti  Kurt Lambeck  Steve Kershaw  Vladimiro Verrubbi  Giuseppe Dai Pra 《Tectonophysics》2006,422(1-4):23-40

A combination of published and new radiometric dates on uplifted Holocene fossil beaches from northeastern Sicily and southern Calabria (southern Italy) is compared with the altitude of the inner margin of the Last Interglacial (LIg) (Late Pleistocene, 124 ka) and older marine terraces in order to gain a regional-scale outline of uplift rates and their temporal changes in a region which is one of the fastest uplifting sectors of the Central Mediterranean Sea. Late Holocene radiocarbon dates from Ioppolo (southern Calabria) and Ganzirri (northeast Sicily), two newly discovered sites are here presented for the first time. The Holocene uplift rates are highest at St. Alessio and Taormina in eastern Sicily (2.4 mm/y) and at Scilla in southwestern Calabria (2.1 mm/y), two sites located across the Messina Straits and which separate the island of Sicily from mainland Italy. Uplift rates decrease towards the south and north from this centre of uplift. Late Holocene uplift rates show an apparent increase of between 64 and 124% when compared with the longer-term uplift rates calculated from the LIg highstand terraces. Furthermore, we discovered that the locations of fastest Late Pleistocene and Late Holocene uplift rates spatially coincide. To what extent the Holocene increase in uplift rates results from incomplete elastic strain release along the major extensional faults which frame the seismotectonic of the area, or indicate a true change in regional tectonic processes, is not resolved. Nonetheless, the heterogeneity of uplift, with a well-defined centre that crosses the Messina Straits, and its persistence at different time-scales indicates a tight connection between wider regional processes and fault-related displacement in controlling crustal instability in this area.  相似文献   

A merger tree with microsolar mass resolution: application to γ-ray emission from subhalo population     

Carlo Giocoli  Lidia Pieri  Giuseppe Tormen  Jorge Moreno 《Monthly notices of the Royal Astronomical Society》2009,395(3):1620-1630

Observations of the southern Cepheid ℓ Car to yield the mean angular diameter and angular pulsation amplitude have been made with the Sydney University Stellar Interferometer at a wavelength of 696 nm. The resulting mean limb-darkened angular diameter is 2.990 ± 0.017 mas (i.e. ± 0.6 per cent) with a maximum-to-minimum amplitude of 0.560 ± 0.018 mas corresponding to 18.7 ± 0.6 per cent in the mean stellar diameter. Careful attention has been paid to uncertainties, including those in measurements, in the adopted calibrator angular diameters, in the projected values of visibility squared at zero baseline, and to systematic effects. No evidence was found for a circumstellar envelope at 696 nm. The interferometric results have been combined with radial displacements of the stellar atmosphere derived from selected radial velocity data taken from the literature to determine the distance and mean diameter of ℓ Car. The distance is determined to be 525 ± 26 pc and the mean radius  169 ± 8 R_⊙  . Comparison with published values for the distance and mean radius shows excellent agreement, particularly when a common scaling factor from observed radial velocity to pulsation velocity of the stellar atmosphere (the p -factor) is used.  相似文献