Magma convection and mixing dynamics as a source of Ultra-Long-Period oscillations     

Antonella Longo  Paolo Papale  Melissa Vassalli  Gilberto Saccorotti  Chiara P. Montagna  Andrea Cassioli  Salvatore Giudice  Enzo Boschi 《Bulletin of Volcanology》2012,74(4):873-880

Many volcanic eruptions are shortly preceded by injection of new magma into a pre-existing, shallow (<10 km) magma chamber, causing convection and mixing between the incoming and resident magmas. These processes may trigger dyke propagation and further magma rise, inducing long-term (days to months) volcano deformation, seismic swarms, gravity anomalies, and changes in the composition of volcanic plumes and fumaroles, eventually culminating in an eruption. Although new magma injection into shallow magma chambers can lead to hazardous event, such injection is still not systematically detected and recognized. Here, we present the results of numerical simulations of magma convection and mixing in geometrically complex magmatic systems, and describe the multiparametric dynamics associated with buoyant magma injection. Our results reveal unexpected pressure trends and pressure oscillations in the Ultra-Long-Period (ULP) range of minutes, related to the generation of discrete plumes of rising magma. Very long pressure oscillation wavelengths translate into comparably ULP ground displacements with amplitudes of order 10⁻⁴–10⁻² m. Thus, new magma injection into magma chambers beneath volcanoes can be revealed by ULP ground displacement measured at the surface.  相似文献   

Autochthonous and allochthonous plant contributions to coastal benthic detritus deposits: a dual-stable isotope study in a volcanic lake     

Loreto Rossi  M. Letizia Costantini  Pasquale Carlino  Antonella di Lascio  David Rossi 《Aquatic Sciences - Research Across Boundaries》2010,72(2):227-236

The high numbers of primary producers represent multiple sources of organic matter accumulating onto lake bottoms. The difficulty of distinguishing the relative contribution to the mixture presents considerable challenges to the analysis of these organic deposits. In this study, dual-stable isotope analysis and IsoSource model were used to identify allochthonous and autochthonous components of detritus deposits (Particulate Organic Matter: POM) at two different bottom slope sites of a volcanic lake (lake Bracciano). Experiments were carried out to calibrate IsoSource on constructed plant mixtures and assess changes in isotope ratios during plant decomposition. IsoSource satisfactorily discriminated the constructed mixture sources with a few exceptions. Changes in isotopic enrichment during decomposition were low, and thus did not represent a confounding variable in the isotopic analysis. By contrast, chemical and geological differences of the study sites were associated with differences in plant δ¹³C and δ¹⁵N values (more than 2‰ within single plant species). At both sites, the isotopic signals of POM fell between polygons delineated by source end members with an evident shift of δ¹³C toward allochthonous sources. POM amount and diversity were greater at the flatter bottom site, where allochthonous contributions were larger than at the other site. In particular, IsoSource ranked species contributions as follows: A. glutinosa > P. australis > A. donax > S. alba > P. nigra > the benthic macroalga Chara sp. at the first site, and A. glutinosa > P. nigra > the aquatic macrophyte C. demersum at the latter. The composition of littoral POM was determined by allochthonous sources in proportion to their relative abundances (as percent land cover) with differences between sites due to bottom slope.  相似文献   

Monitoring toxic microalgae Ostreopsis (dinoflagellate) species in coastal waters of the Mediterranean Sea using molecular PCR-based assay combined with light microscopy   总被引：1，自引：0，他引：1  

Cecilia Battocchi  Magda Vila  Samuela Capellacci  Albert Reñé  Antonella Penna 《Marine pollution bulletin》2010,60(7):1074-7059

A molecular PCR-based assay was developed and applied to macrophyte and seawater samples containing mixed microphytobenthic and phytoplanktonic assemblages, respectively, in order to detect toxic Ostreopsis species in Mediterranean Sea. The specificity and sensitivity of the molecular PCR assay were assessed with both plasmidic and genomic DNA of the target genus or species using taxon-specific primers in the presence of background macrophyte DNA. The PCR molecular technique allowed rapid detection of the Ostreopsis cells, even at abundances undetectable within the resolution limit of the microscopy technique. Species-specific identification of Ostreopsis was determined only by PCR-based assay, due to the inherent difficulty of morphological identification in field samples. In the monitoring of the toxic Ostreopsis blooms PCR-based methods proved to be effective tools complementary to microscopy for rapid and specific detection of Ostreopsis and other toxic dinoflagellates in marine coastal environments.  相似文献   

On the seismic performance of straight integral abutment bridges: From advanced numerical modelling to a practice-oriented analysis method     

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   

Shaking table tests on a masonry building monitored using smart bricks: Damage detection and localization     

Andrea Meoni  Antonella D'Alessandro  Nicola Cavalagli  Massimiliano Gioffré  Filippo Ubertini 《地震工程与结构动力学》2019,48(8):910-928

The seismic behavior of unreinforced masonry buildings is typically characterized by premature brittle collapse mechanisms that can cause serious consequences for the protection of human lives and for the preservation of historical and cultural heritage. Structural health monitoring can be a powerful tool enabling a quick post-earthquake assessment of the structure's performance, but its applications are still scarce as a consequence of the severe limitations affecting off-the-shelf sensing technologies, in terms of local nature of the measurements, costs, as well as long-term behavior, installation, and maintenance. To overcome some of these limitations, the authors have recently proposed a new sensing technology, called “smart brick,” that is a durable clay brick doped with stainless steel microfibers, working as a smart strain sensor for masonry buildings. This paper presents the first full-scale application of smart bricks, used for detecting and localizing progressive earthquake-induced damage in an unreinforced masonry building subjected to shaking table tests. Smart bricks are employed to detect changes in load paths on masonry walls, comparing strain measurements acquired after each step of the seismic sequence with those referring to the undamaged structure. Experimental results are interpreted using a 3D finite element model built to reproduce the shaking table tests. Overall, the results demonstrate that the smart bricks can effectively reveal local permanent changes in structural conditions following a progressive damage, therefore being apt for earthquake-induced damage detection and localization.  相似文献   

On the scale dependence of earthquake stress drop     

Massimo Cocco  Elisa Tinti  Antonella Cirella 《Journal of Seismology》2016,20(4):1151-1170

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Uranium Groundwater Monitoring and Seismic Analysis: A Case Study of the Gran Sasso Hydrogeological Basin,Italy     

Marta Ciarletti  Wolfango Plastino  Antonella Peresan  Stefano Nisi  Lorenzo Copia  Giuliano F. Panza  Pavel P. Povinec 《Pure and Applied Geophysics》2016,173(4):1079-1095

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Modelling background seismicity components identified by nearest neighbour and stochastic declustering approaches: the case of Northeastern Italy     

Benali  Amel  Peresan  Antonella  Varini  Elisa  Talbi  Abdelhak 《Stochastic Environmental Research and Risk Assessment (SERRA)》2020,34(6):775-791

Stochastic Environmental Research and Risk Assessment - An adequate characterization of the temporal features of background seismicity, namely after removal of temporally and spatially clustered...  相似文献   

Visible–near infrared spectral indices for mapping mineralogy and chemistry with OSIRIS‐REx     

Hannah H. Kaplan  Victoria E. Hamilton  Ellen S. Howell  F. Scott Anderson  M. Antonella Barrucci  John Brucato  Thomas H. Burbine  Beth E. Clark  Ed A. Cloutis  Harold C. Connolly  Elisabetta Dotto  Joshua P. Emery  Sonia Fornasier  Cateline Lantz  Lucy F. Lim  Frederic Merlin  Alice Praet  Dennis C. Reuter  Scott A. Sandford  Amy A. Simon  Driss Takir  Dante S. Lauretta 《Meteoritics & planetary science》2020,55(4):744-765

The primary objective of the Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS‐REx) mission is to return to Earth a pristine sample of carbonaceous material from the primitive asteroid (101955) Bennu. To support compositional mapping of Bennu as part of sample site selection and characterization, we tested 95 spectral indices on visible to near infrared laboratory reflectance data from minerals and carbonaceous meteorites. Our aim was to determine which indices reliably identify spectral features of interest. Most spectral indices had high positive detection rates when applied to spectra of pure, single‐component materials. The meteorite spectra have fewer and weaker absorption features and, as a result, fewer detections with the spectral indices. Indices targeting absorptions at 0.7 and 2.7–3 μm, which are attributable to hydrated minerals, were most successful for the meteorites. Based on these results, we identified a set of 17 indices that are most likely to be useful at Bennu. These indices detect olivines, pyroxenes, carbonates, water/OH‐bearing minerals, serpentines, ferric minerals, and organics. Particle size and albedo are known to affect band depth but had a negligible impact on interpretive success with spectral indices. Preliminary analysis of the disk‐integrated Bennu spectrum with these indices is consistent with expectations given the observed absorption near 3 μm. Our study prioritizes spectral indices to be used for OSIRIS‐REx spectral analysis and mapping and informs the reliability of all index‐derived data products, including a science value map for sample site selection.  相似文献   

Ecotoxicological and human health risk in a petrochemical district of southern Italy   总被引：2，自引：0，他引：2  

Ausili A  Gabellini M  Cammarata G  Fattorini D  Benedetti M  Pisanelli B  Gorbi S  Regoli F 《Marine environmental research》2008,66(1):215-217

An ecotoxicological investigation has been carried in the petrochemical district of Priolo (Sicily, Italy), one of the largest in Europe. Results indicated a severe mercury contamination in sediments sampled near a chloro-alkali plant. A clear bioavailability of this element was demonstrated in mussels Mytilus galloprovincialis (both native and translocated) and the benthic fish Mullus barbatus, which also exhibited marked genotoxic damages. The elevated mercury concentrations in marine organisms are a serious concern for human health; according to the national average fish consumption, the provisional tolerable weekly intake (PTWI) of Hg would be easily exceeded by at least 4 to 12 fold. Such toxicological risk is of particular importance for pregnant women, being possibly involved in the elevated frequency of neonatal malformations.  相似文献