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161.
162.
The purpose of this work is to evaluate under what conditions it is feasible and with what accuracy it is possible to locate the nucleation point of a large earthquake, given the availability of aftershocks located with high precision by the deployment of a local network. We experiment with several approaches and apply them lo the location of the epicentre of the 1980 November 23 Irpinia earthquake ( M w = 6.9).
First we use local Pg phases selected to optimize the azimuthal coverage, obtaining a well-constrained location with a small statistical error, which typically underestimates the true hypocentre uncertainty.
We then exploit the relative location technique, obtaining stable, almost coincident solutions under three conditions: (1) using multiple independent master events to derive an average epicentre; (2) fitting simultaneously the larger data set for all available master events, using a forward approach; (3) conducting an a priori evaluation of the statistics of station and master events to separate model uncertainties and improve the statistical accuracy of the relative locations. Moreover, only by introducing station statistics can we achieve the desired accuracy of ≅ 1 km in constraining the rupture nucleation point of this large earthquake, and we show that the application of the relative location technique to uncleaned, unweighted data for a single master event provides only a crude epicentre with a confidence ellipse deceivingly smaller than the true hypocentre uncertainty.
The revised epicentre for the 1980 November 23 Irpinia earthquake (48.803 °N-15.302°E) validates the class of multidisciplinary reconstructions of the source process such as the model of Valensise et al. (1989), based on the hypocentre of Westaway & Jackson (1987), and is shifted by almost 13 km to the NW of the epicentre recently proposed by Westaway (1992). 相似文献
First we use local P
We then exploit the relative location technique, obtaining stable, almost coincident solutions under three conditions: (1) using multiple independent master events to derive an average epicentre; (2) fitting simultaneously the larger data set for all available master events, using a forward approach; (3) conducting an a priori evaluation of the statistics of station and master events to separate model uncertainties and improve the statistical accuracy of the relative locations. Moreover, only by introducing station statistics can we achieve the desired accuracy of ≅ 1 km in constraining the rupture nucleation point of this large earthquake, and we show that the application of the relative location technique to uncleaned, unweighted data for a single master event provides only a crude epicentre with a confidence ellipse deceivingly smaller than the true hypocentre uncertainty.
The revised epicentre for the 1980 November 23 Irpinia earthquake (48.803 °N-15.302°E) validates the class of multidisciplinary reconstructions of the source process such as the model of Valensise et al. (1989), based on the hypocentre of Westaway & Jackson (1987), and is shifted by almost 13 km to the NW of the epicentre recently proposed by Westaway (1992). 相似文献
163.
Correlation between nitrate concentration in groundwater and parameters affecting aquifer intrinsic vulnerability 总被引:3,自引:0,他引:3
This paper is the result of a study which was carried out in order to verify if the traditional methods to evaluate the intrinsic
vulnerability or vulnerability related parameters, are able to clarify the problem of nitrate pollution in groundwater. In
particular, the aim was to evaluate limitations and problems connected to aquifer vulnerability methods applied to nitrate
contamination prevision in groundwater. The investigation was carried out by comparing NO3
− concentrations, measured in March and November 2004 in the shallow aquifer, and the vulnerability classes, obtained by using
GOD and TOT methods. Moreover, it deals with a comparison between NO3
− concentrations and single parameters (depth to water table, land use and nitrogen input). The study area is the plain sector
of Piemonte (Northern Italy), where an unconfined aquifer nitrate contamination exists. In this area the anthropogenic presence
is remarkable and the input of N-fertilizers and zootechnical effluents to the soil cause a growing amount of nitrates in
groundwater. This approach, used in a large area (about 10,000 km2) and in several monitoring wells (about 500), allowed to compare the efficiency of different vulnerability methods and to
verify the importance of every parameter on the nitrate concentrations in the aquifer. Furthermore it allowed to obtain interesting
correlations in different hydrogeological situations. Correlations between depth to water table, land use and nitrogen input
to the soil with nitrate concentrations in groundwater show unclear situations: in fact these comparisons describe the phenomenon
trend and highlight the maximum nitrate concentrations for each circumstance but often show wide ranges of possible nitrate
concentrations. The same situation could be observed by comparing vulnerability indexes and nitrate concentrations in groundwater.
These results suggest that neither single parameters nor vulnerability methods (GOD and TOT) are able to describe individually
the complex phenomena affecting nitrate concentrations in soil, subsoil and groundwater. In particular, the traditional methods
for vulnerability analysis do not analyze physical processes in aquifers, such as denitrification and nitrate dilution. According
to a recent study in the shallow unconfined aquifer of the Piemonte plain, dilution can be considered as the main cause for
nitrate attenuation in groundwater. 相似文献
164.
Gervasio Degrazia Domenico Anfossi Haroldo Fraga De Campos Velho Enrico Ferrero 《Boundary-Layer Meteorology》1998,86(3):525-534
A new method for deriving the Lagrangian decorrelation time scales for inhomogeneous turbulence is described. The expression for the time scales here derived for the convective boundary layer is compared to those estimated by Hanna during the Phoenix experiment. Then the values of C0, the Lagrangian velocity structure function constant, and of Bi, the Lagrangian velocity spectrum constant, were evaluated from the Eulerian velocity spectra and from the Lagrangian time scales derived, under unstable conditions, from Taylor's statistical diffusion theory. The numerical coefficient of the lateral and vertical Lagrangian spectra in the inertial subrange was found equal to 0.21, in good agreement with previous experimental estimates. 相似文献
165.
Unidata’s Common Data Model mapping to the ISO 19123 Data Model 总被引:1,自引:1,他引:0
Access to real-time distributed Earth and Space Science (ESS) information is essential for enabling critical Decision Support
Systems (DSS). Thus, data model interoperability between the ESS and DSS communities is a decisive achievement for enabling
cyber-infrastructure which aims to serve important societal benefit areas. The ESS community is characterized by a certain
heterogeneity, as far as data models are concerned. Recent spatial data infrastructures implement international standards
for the data model in order to achieve interoperability and extensibility. This paper presents well-accepted ESS data models,
introducing a unified data model called the Common Data Model (CDM). CDM mapping into the corresponding elements of the international
standard coverage data model of ISO 19123 is presented and discussed at the abstract level. The mapping of CDM scientific
data types to the ISO coverage model is a first step toward interoperability of data systems. This mapping will provide the
abstract framework that can be used to unify subsequent efforts to define appropriate conventions along with explicit agreed-upon
encoding forms for each data type. As a valuable case in point, the content mapping rules for CDM grid data are discussed
addressing a significant example.
相似文献
Lorenzo BigagliEmail: URL: www.imaa.cnr.it |
166.
D’Aniello Andrea Cozzolino Luca Cimorelli Luigi Della Morte Renata Pianese Domenico 《Natural Hazards》2015,75(2):1403-1433
Natural Hazards - In this paper, it is described the development and the assessment of a 1D numerical procedure for the simulation of debris flow phenomena. The procedure focuses on: (1) the... 相似文献
167.
168.
Domenico Montanari Chiara Del Ventisette Marco Bonini Federico Sani 《Geological Journal》2007,42(5):455-476
We present the results of a study of the Vena del Gesso Basin (Romagna Apennines, Italy) integrating field analyses and analogue modelling. This basin represents one of the best‐preserved top‐thrust basins in the Northern Apennines foreland and is one of the few examples where primary evaporites, related to the Messinian salinity crisis of the Mediterranean, widely crop out. The structural style affecting the Messinian gypsum is examined to get insights into the mechanism responsible for the overall deformation features recognizable in the area. The evaporites are completely detached at the base and widespread back‐thrusts, repeatedly doubling these deposits, strongly contrast with the regional forelandward vergence of structures in the Apennines. On the basis of the comparison between field data and experimental results, the features characterising this area can be described as the result of the deformation linked to the sequential activation of an obliquely propagating passive‐roof duplex. Analogue models evidenced the major role played (1) by syntectonic erosion that promoted the development of passive‐roof duplex style, as well as (2) the role of décollement level pinch‐out that determined an oblique progression of deformation. Finally our data lead to reconsider the palaeoenvironmental reconstruction concerning the onset of the Messinian salinity crisis in the Mediterranean. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
169.
170.
Andrea Marchi Domenico Gallese Davide Noè Gorini Paolo Franchin Luigi Callisto 《地震工程与结构动力学》2023,52(1):164-182
The seismic performance of integral abutment bridges (IABs) is affected by the interaction with the surrounding soil, and specifically by the development of interaction forces in the embankment-abutment and soil-piles systems. In principle, these effects could be evaluated by means of highly demanding numerical computations that, however, can be carried out only for detailed studies of specific cases. By contrast, a low-demanding analysis method is needed for a design-oriented assessment of the longitudinal seismic performance of IABs. To this purpose, the present paper describes a design technique in which the frequency- and amplitude-dependency of the soil-structure interaction is modelled in a simplified manner. Specifically, the method consists of a time-domain analysis of a simplified soil-bridge model, in which soil-structure interaction is simulated by means of distributed nonlinear springs connecting a free-field ground response analysis model to the structural system. The results of this simplified method are validated against the results of advanced numerical analyses, considering different seismic scenarios. In its present state of development, the proposed simplified nonlinear model can be used for an efficient evaluation of the longitudinal response of straight IABs and can constitute a starting point for a prospective generalisation to three-dimensional response. 相似文献