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231.
Shallow landslides in pyroclastic soils: a distributed modelling approach for hazard assessment 总被引:3,自引:0,他引:3
Paolo Frattini Giovanni B. Crosta Nicoletta Fusi Paolo Dal Negro 《Engineering Geology》2004,73(3-4):277-295
An effective assessment of shallow landslide hazard requires spatially distributed modelling of triggering processes. This is possible by using physically based models that allow us to simulate the transient hydrological and geotechnical processes responsible for slope instability. Some simplifications are needed to address the lack of data and the difficulty of calibration over complex terrain at the catchment's scale. We applied two simple hydrological models, coupled with the infinite slope stability analysis, to the May 1998 landslide event in Sarno, Southern Italy. A quasi-dynamic model (Barling et al., 1994) was used to model the contribution to instability of lateral flow by simulating the time-dependent formation of a groundwater table in response to rainfall. A diffusion model [Water Resour. Res. 36 (2000) 1897] was used to model the role of vertical flux by simulating groundwater pressures that develop in response to heavy rainstorms. The quasi-dynamic model overestimated the slope instability over the whole area (more than 16%) but was able to predict correctly slope instability within zero order basins where landslides occurred and developed into large debris flows. The diffusion model simulated correctly the triggering time of more than 70% of landslides within an unstable area amounting to 7.3% of the study area. These results support the hypothesis that both vertical and lateral fluxes were responsible for landslide triggering during the Sarno event, and confirm the utility of such models as tools for hazard planning and land management. 相似文献
232.
Paolo Lanzano 《Astrophysics and Space Science》1976,45(2):419-431
The integralsJ
,
m
were introduced by Kopal for the numerical evaluation of the light changes exhibited by eclipsing binaries when both the tidal and rotational distrotions are taken into account.This paper is a sequel to a previous one to appear in this journal and aims at ascertaining some recursion formulae for these integrals to alleviate the computational complexity of the problem.Using a relationship existing between theJ-integrals and the Appell hypergeometric series of the first kind, we have been able to obtain recursion formulae affecting all three parametersm , of these integrals. The present stage of development has also allowed for a complete enumeration of all independent recursion formulae applicable to the case of partial eclipses.Various recursion formulae, given here for the first time, generalize previous results by Kopal which were valid form=0 ory=0. 相似文献
233.
A procedure for landslide susceptibility zonation by the conditional analysis method 总被引:7,自引:0,他引:7
Numerous methods have been proposed for landslide probability zonation of the landscape by means of a Geographic Information System (GIS). Among the multivariate methods, i.e. those methods which simultaneously take into account all the factors contributing to instability, the Conditional Analysis method applied to a subdivision of the territory into Unique Condition Units is particularly straightforward from a conceptual point of view and particularly suited to the use of a GIS. In fact, working on the principle that future landslides are more likely to occur under those conditions which led to past instability, landslide susceptibility is defined by computing the landslide density in correspondence with different combinations of instability factors. The conceptual simplicity of this method, however, does not necessarily imply that it is simple to implement, especially as it requires rather complex operations and a high number of GIS commands. Moreover, there is the possibility that, in order to achieve satisfactory results, the procedure has to be repeated a few times changing the factors or modifying the class subdivision. To solve this problem, we created a shell program which, by combining the shell commands, the GIS Geographical Research Analysis Support System (GRASS) commands and the gawk language commands, carries out the whole procedure automatically. This makes the construction of a Landslide Susceptibility Map easy and fast for large areas too, and even when a high spatial resolution is adopted, as shown by application of the procedure to the Parma River basin, in the Italian Northern Apennines. 相似文献
234.
Hierarchical spatial interaction among the Italian regions: a nonlinear relative dynamics approach 总被引:2,自引:2,他引:0
Regional interactions and spillover effects should be considered as important factors in growth analysis of regional economies.
Using modified versions of the Dendrinos–Sonis model, this paper analyses the spatial hierarchical system of Italy. The interaction
among Italian regions is considered at three different levels of spatial aggregation, the NUTS-1, NUTS-2 and NUTS-3 levels.
Compared to more popular spatial econometric approaches, the Dendrinos–Sonis model and its extensions provide greater flexibility
in the way interaction between regions is handled but the results strongly depend on the choice of a reference region.
相似文献
Geoffrey J. D. HewingsEmail: |
235.
Meng Ding Ya-Peng Zhang Yong-Jie Zhang Yuan-Peng Wang Tie-Kuang Dong Antonio De Benedittis Paolo Bernardini Fang Fang Yao Li Jie Liu Peng-Xiong Ma Zhi-Yu Sun Valentina Gallo Stefania Vitillo Zhao-Min Wang Yu-Hong Yu Chuan Yue Qiang Yuan Yong Zhou Yun-Long Zhang 《天文和天体物理学研究(英文版)》2019,(3):145-154
The DArk Matter Particle Explorer(DAMPE) is a space-borne apparatus for detecting the highenergy cosmic-ray-like electrons, γ-rays, protons and heavy ions. The Plastic Scintillator Detector(PSD)is the top-most sub-detector of the DAMPE. The PSD is designed to measure the charge of incident highenergy particles and it also serves as a veto detector for discriminating γ-rays from charged particles. In this paper, a PSD on-orbit calibration procedure is described, which includes the five steps of pedestal, dynode correlation, response to minimum-ionizing particles, light attenuation function and energy reconstruction.A method for reconstructing the charge of incident high energy cosmic-ray particles is introduced. The detection efficiency of each PSD strip is verified to be above 99.5%; the total efficiency of the PSD for charged particles is above 99.99%. 相似文献
236.
The role of carbon dioxide in the dynamics of magma ascent in explosive eruptions is investigated by means of numerical modeling.
The model is steady, one-dimensional, and isothermal; it calculates the separated flow of gas and a homogeneous mixture of
liquid magma and crystals. The magma properties are calculated on the basis of magma composition and crystal content and are
allowed to change along the conduit due to pressure decrease and gas exsolution. The effect of the presence of a two-component
(water + carbon dioxide) exsolving gas phase is investigated by performing a parametric study on the CO2/(H2O+CO2) ratio, which is allowed to vary from 0 to 0.5 at either constant total volatile or constant water content. The relatively
insoluble carbon dioxide component plays an important role in the location of the volatile-saturation and magma-fragmentation
levels and in the distribution of the flow variables in the volcanic conduit. In detail, the results show that an increase
of the proportion of carbon dioxide produces a decrease of the mass flow rate, pressure, and exit mixture density, and an
increase of the exit gas volume fraction and depth of the fragmentation level. A relevant result is the different role played
by water and carbon dioxide in the eruption dynamics; an increasing amount of water produces an increase of the mass flow
rate, and an increasing amount of carbon dioxide produces a decrease. Even small amounts of carbon dioxide have major consequences
on the eruption dynamics, implying that the multicomponent nature of the volcanic gas must be taken into account in the prediction
of the eruption scenario and the forecasting of volcanic hazard.
Received: 6 March 1998 / Accepted: 28 October 1998 相似文献
237.
Mohsen Kohrangi Sreeram Reddy Kotha Paolo Bazzurro 《Bulletin of Earthquake Engineering》2018,16(1):45-65
Average spectral acceleration, AvgSA, is defined as the geometric mean of spectral acceleration values over a range of periods and it is a ground motion intensity measure used for structural response prediction. One of its advantages stands on the assumption that its distribution is computable from the available GMPEs for spectral acceleration, GMPE-SA, (called here indirect method) without the need for deriving new specific GMPEs for AvgSA, GMPE-AvgSA, (called here direct method). To what extent this assumption is valid, however, has never been verified. As such, we derived an empirical GMPE-AvgSA based on RESORCE ground motion dataset and we compared its predicted values with those from a GMPE-SA via the indirect approach. As expected, the results show that the indirect approach yields median AvgSA estimates that are identical to those of the direct approach. However, the estimates of AvgSA variance of the two methods are identical only if both the GMPE-SA and their empirical correlation coefficients among different SA ordinates are derived from the same record dataset. 相似文献
238.
Carlo Del Gaudio Paolo Ricci Gerardo Mario Verderame 《Bulletin of Earthquake Engineering》2018,16(10):4581-4605
The simplified mechanical method POST (PushOver on Shear Type models) for seismic vulnerability assessment of RC buildings is used in this study to derive damage scenarios for a database of 7597 RC buildings subjected to the 2009 L’Aquila earthquake. POST allows the evaluation of fragility curves through the determination of the non-linear static response of RC buildings in closed form, assuming the hypothesis of shear type behaviour, and considering the influence of infill panels both in the derivation of structural response and in assessment of building damage, which is defined according to the European Macroseismic Scale EMS-98. The aim of the present study is to provide a much more significant and reliable validation of the methodology, thanks to a much wider database compared to previous studies, and based on a different application of the methodology, i.e. at building class-level instead of single building-level. To this aim, the main geometrical-typological characteristics of the analysed buildings (number of storeys, age of construction, building area) have been statistically characterized based on data collected from post-earthquake AeDES survey forms, considering both the variability of each single parameter and the correlation that exists between one parameter and the other. This also allows to analyse the effectiveness of the adopted analytical procedure in predicting the general trends of observed damage with these parameters, showing a good agreement between observed and predicted trends. The overall predicted damage scenarios are compared with the corresponding observed ones, collected from AeDES survey forms, highlighting, again, a good agreement. Finally, the assumed mechanical interpretation of damage classification of EMS-98 is validated through the comparison between the distributions of damage to vertical structures and infill panels and the corresponding observed post-earthquake damage data. 相似文献
239.
Francesca Barbagallo Melina Bosco Edoardo M. Marino Pier Paolo Rossi 《地震工程与结构动力学》2018,47(13):2682-2707
A design procedure for seismic retrofitting of concentrically and eccentrically braced frame buildings is proposed and validated in this paper. Rocking walls are added to the existing system to ensure an almost uniform distribution of the interstorey displacement in elevation. To achieve direct and efficient control over the seismic performance, the design procedure is founded on the displacement‐based approach and makes use of overdamped elastic response spectra. The top displacement capacity of the building is evaluated based on a rigid lateral deformed configuration of the structure and on the ductility capacity of the dissipative members of the braced frames. The equivalent viscous damping ratio of the braced structure with rocking walls is calculated based on semi‐empirical relationships specifically calibrated in this paper for concentrically and eccentrically braced frames. If the equivalent viscous damping ratio of the structure is lower than the required equivalent viscous damping ratio, viscous dampers are added and arranged between the rocking walls and adjacent reaction columns. The design internal forces of the rocking walls are evaluated considering the contributions of more than one mode of vibration. The proposed design procedure is applied to a large set of archetype braced frame buildings and its effectiveness verified by nonlinear dynamic analysis. 相似文献
240.