A prototype system for space–time assessment of rainfall-induced shallow landslides in Italy     

Lorella Montrasio  Roberto Valentino  Angela Corina  Lauro Rossi  Roberto Rudari 《Natural Hazards》2014,74(2):1263-1290

In the last decades, physically based distributed models turned out rather promising to achieve the space–time assessment of shallow landslides at large spatial scale. This technical note deals with the application of a physically based stability model named Shallow Landslides Instability Prediction (SLIP), which has been adopted by the Department of National Civil Protection of Italy as a prototype early warning system for rainfall-induced shallow landslides on national scale. The model is used as a main methodology to create space–time shallow landslide susceptibility maps based on a simple deterministic slope-stability approach, combined with high-resolution rainfall information and geographic information system-based geospatial datasets. The safety factor as an index to measure slope instability is modeled as function of topographic, geologic, geotechnical and hydrologic variables. Although the main aim of this work was to prove the operational viability of such model on a nationwide domain and some simplification are adopted at this stage, hind cast tests on some relevant case histories of shallow landslides occurred between October 2009 and October 2011 showed that the model has skill in representing both timing and location of those shallow landslides.  相似文献   

Geometallurgical Modeling at Olympic Dam Mine, South Australia     

Jeff B. Boisvert  Mario E. Rossi  Kathy Ehrig  Clayton V. Deutsch 《Mathematical Geosciences》2013,45(8):901-925

Modeling of geometallurgical variables is becoming increasingly important for improved management of mineral resources. Mineral processing circuits are complex and depend on the interaction of a large number of properties of the ore feed. At the Olympic Dam mine in South Australia, plant performance variables of interest include the recovery of Cu and U₃O₈, acid consumption, net recovery, drop weight index, and bond mill work index. There are an insufficient number of pilot plant trials (841) to consider direct three-dimensional spatial modeling for the entire deposit. The more extensively sampled head grades, mineral associations, grain sizes, and mineralogy variables are modeled and used to predict plant performance. A two-stage linear regression model of the available data is developed and provides a predictive model with correlations to the plant performance variables ranging from 0.65–0.90. There are a total of 204 variables that have sufficient sampling to be considered in this regression model. After developing the relationships between the 204 input variables and the six performance variables, the input variables are simulated with sequential Gaussian simulation and used to generate models of recovery of Cu and U₃O₈, acid consumption, net recovery, drop weight index, and bond mill work index. These final models are suitable for mine and plant optimization.  相似文献   

An analytical method for the evaluation of the in-plan irregularity of non-regularly asymmetric buildings     

Melina Bosco  Edoardo M. Marino  Pier Paolo Rossi 《Bulletin of Earthquake Engineering》2013,11(5):1423-1445

This paper describes a new method for the evaluation of the static eccentricity $e_{s}$ and the ratio $\Omega _{\uptheta } $ of uncoupled torsional to lateral frequencies in real multi-storey buildings. The above-mentioned parameters greatly affect the lateral-to-torsional coupling of the response of asymmetric systems and thus are of paramount importance in the assessment of the in-plan irregularity of buildings. The proposed method, which is a generalization of that suggested by Calderoni et al. (Earthq Spectra 18(2):219–231, 2002), allows the calculation of the static eccentricity $e_{s}$ and the ratio $\Omega _{\uptheta } $ from the structural response to arbitrary distributions of forces and torsional couples. The effectiveness of the method is validated on some regularly and non-regularly asymmetric buildings characterised by different in-plan irregularity. The analyses demonstrate that the results of the method are rigorous in the case of regularly asymmetric systems and only slightly depend upon the heightwise distribution of the forces in the case of non-regularly asymmetric systems. Finally, the values of the static eccentricity $e_{s}$ and the ratio $\Omega _{\uptheta } $ resulting from the proposed method are compared to those obtained by means of the procedure suggested by Makarios and Anastassiadis in (Struct Des Tall Spec Build 7(1):33–55, 1998a; Struct Des Tall Spec Build 7(1):57–71, 1998b) .  相似文献   

Comparison of nonlinear static methods for the assessment of asymmetric buildings     

Melina Bosco  Aurelio Ghersi  Edoardo M. Marino  Pier Paolo Rossi 《Bulletin of Earthquake Engineering》2013,11(6):2287-2308

Traditional nonlinear static methods, e.g. the original version of the N2 method implemented in Eurocode 8, are not always effective in the assessment of asymmetric structures because of the errors committed in the evaluation of the torsional response. To overcome this shortcoming, two methods have recently been suggested by Kreslin and Fajfar (Bull Earthquake Eng 10(2):695–715, 2012) and Bosco et al. (Earthq Eng Struct Dyn 41:1751–1773, 2012). In particular, the method proposed by Kreslin and Fajfar adjusts the results of the nonlinear static analysis by means of those of a standard modal response spectrum analysis. In the method proposed by Bosco et al., the researchers suggested the use of two nonlinear static analyses characterized by lateral forces applied to different points of the deck. In this paper, the two improved nonlinear static methods and the original N2 method are applied to predict the maximum dynamic response of single- and multi-storey systems subjected to artificial and recorded accelerograms. The results highlight that the improved nonlinear static methods provide estimates which are more accurate than those of the original N2 method. Further, the comparison of the results identifies the range of the structural properties within which the original N2 method is still reliable and the range within which one of the two improved methods should be preferred.  相似文献   

Improving basin scale shallow landslide modelling using reliable soil thickness maps   总被引：3，自引：0，他引：3  

Samuele Segoni  Guglielmo Rossi  Filippo Catani 《Natural Hazards》2012,61(1):85-101

Soil thickness is a well-known factor controlling shallow landsliding. Notwithstanding, its spatial organisation over large areas is poorly understood, and in basin scale slope analyses it is often established using simple methods. In this paper, we apply five different soil thickness models in two test sites, and we use the obtained soil thickness maps to feed a slope stability model. Validation quantifies how errors in soil thickness influence the resulting factor of safety and points out which method grants the best results. In particular, in our cases, slope-derived soil thickness patterns produced the worst slope stability assessment, while the use of reliable soil thickness maps obtained by means of a more complex geomorphologically indexed model improved shallow landslides modelling.  相似文献   

Unbiased estimates of galaxy scaling relations from photometric redshift surveys     

Graziano Rossi  Ravi K. Sheth 《Monthly notices of the Royal Astronomical Society》2008,387(2):735-740

Many physical properties of galaxies correlate with one another, and these correlations are often used to constrain galaxy formation models. Such correlations include the colour–magnitude relation, the luminosity–size relation, the fundamental plane, etc. However, the transformation from observable (e.g. angular size, apparent brightness) to physical quantity (physical size, luminosity) is often distance dependent. Noise in the distance estimate will lead to biased estimates of these correlations, thus compromising the ability of photometric redshift surveys to constrain galaxy formation models. We describe two methods which can remove this bias. One is a generalization of the V _max method, and the other is a maximum-likelihood approach. We illustrate their effectiveness by studying the size–luminosity relation in a mock catalogue, although both methods can be applied to other scaling relations as well. We show that if one simply uses photometric redshifts one obtains a biased relation; our methods correct for this bias and recover the true relation.  相似文献   

Resonant dynamics of Medium Earth Orbits: space debris issues     

Alessandro Rossi 《Celestial Mechanics and Dynamical Astronomy》2008,100(4):267-286

The Medium Earth Orbit region is the home of the navigation constellations. It is shown how the orbits of these constellations of satellites are strongly affected by the so-called inclination dependent luni-solar resonances. The analytical theory of these resonances is recalled and a large set of numerical integrations is used to investigate the stability of the orbits of the constellations over very long time spans. The stability issue is important in the definition of possible disposal strategies for the constellation spacecraft, after their end-of-life. Two possible disposal strategies are envisaged involving either stable or unstable orbits (from the eccentricity growth point of view). In particular it is shown how, to have disposal orbits with moderately short lifetime (of the orders of 40–50 years), a very large disposal maneuver would be required to rise the inital eccentricity to values above ~ 0.3.  相似文献   

Membrane Interface Probe Protocol for Contaminants in Low‐Permeability Zones     

David T. Adamson  Steven Chapman  Nicholas Mahler  Charles Newell  Beth Parker  Seth Pitkin  Michael Rossi  Mike Singletary 《Ground water》2014,52(4):550-565

Accurate characterization of contaminant mass in zones of low hydraulic conductivity (low k) is essential for site management because this difficult‐to‐treat mass can be a long‐term secondary source. This study developed a protocol for the membrane interface probe (MIP) as a low‐cost, rapid data‐acquisition tool for qualitatively evaluating the location and relative distribution of mass in low‐k zones. MIP operating parameters were varied systematically at high and low concentration locations at a contaminated site to evaluate the impact of the parameters on data quality relative to a detailed adjacent profile of soil concentrations. Evaluation of the relative location of maximum concentrations and the shape of the MIP vs. soil profiles led to a standard operating procedure (SOP) for the MIP to delineate contamination in low‐k zones. This includes recommendations for: (1) preferred detector (ECD for low concentration zones, PID or ECD for higher concentration zones); (2) combining downlogged and uplogged data to reduce carryover; and (3) higher carrier gas flow rate in high concentration zones. Linear regression indicated scatter in all MIP‐to‐soil comparisons, including R² values using the SOP of 0.32 in the low concentration boring and 0.49 in the high concentration boring. In contrast, a control dataset with soil‐to‐soil correlations from borings 1‐m apart exhibited an R² of ≥0.88, highlighting the uncertainty in predicting soil concentrations using MIP data. This study demonstrates that the MIP provides lower‐precision contaminant distribution and heterogeneity data compared to more intensive high‐resolution characterization methods. This is consistent with its use as a complementary screening tool.  相似文献   

Temporal correlations and clustering of landslides     

Annette Witt  Bruce D. Malamud  Mauro Rossi  Fausto Guzzetti  Silvia Peruccacci 《地球表面变化过程与地形》2010,35(10):1138-1156

This paper examines temporal correlations and temporal clustering of a proxy historical landslide time series, 2255 reported landslides 1951–2002, for an area in the Emilia‐Romagna Region, Italy. Landslide intensity is measured by the number of reported landslides in a day (D_L) and in an ‘event’ (S_event) of consecutive days with landsliding. The non‐zero values in both time series D_L and S_event are unequally spaced in time, and have heavy‐tailed frequency‐size distributions. To examine temporal correlations, we use power‐spectral analysis (Lomb periodogram) and surrogate data analysis, confronting our original D_L and S_event time series with 1000 shuffled (uncorrelated) versions. We conclude that the landslide intensity series D_L has strong temporal correlations and S_event has likely temporal correlations. To examine temporal clustering in D_L and S_event, we consider extremes over different landslide intensity thresholds. We first examine the statistical distribution of interextreme occurrence times, τ, and find Weibull distributions with parameter γ << 1·0 [D_L] and γ < 1·0 [S_event]; thus D_L and S_event each have temporal correlations, but S_event to a lesser degree. We next examine correlations between successive interextreme occurrence times, τ. Using autocorrelation analysis applied to τ, combined with surrogate data analysis, we find for D_L linear correlations in τ, but for S_event inconclusive results. However, using Kendall's rank correlation analysis we find for both D_L and S_event the series of τ are strongly correlated. Finally, we apply Fano Factor analysis, finding for both D_L and S_event the timings of extremes over a given threshold exhibit a fractal structure and are clustered in time. In this paper, we provide a framework for examining time series where the non‐zero values are strongly unequally spaced and heavy‐tailed, particularly important in the Earth Sciences due to their common occurrence, and find that landslide intensity time series exhibit temporal correlations and clustering. Many landslide models currently are designed under the assumption that landslides are uncorrelated in time, which we show is false. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Linear time history analysis for the out-of-plane seismic demand of infill walls in RC framed buildings     

Alessandra De Angelis  Marisa Pecce  Fernando Rossi 《Bulletin of Earthquake Engineering》2015,13(11):3325-3352

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