From structure- to erosion-controlled subsiding calderas: evidence thresholds and mechanics     

Nobuo Geshi  Valerio Acocella  Joel Ruch 《Bulletin of Volcanology》2012,74(6):1553-1567

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Kinematic setting and structural control of arc volcanism     

Valerio Acocella  Francesca Funiciello 《Earth and Planetary Science Letters》2010,289(1-2):43-53

The evaluation of the kinematic setting and the structural control of volcanic arcs are important in defining the tectono-magmatic processes along convergent plate boundaries. However, our knowledge is fragmented and the available data highlight different behaviours. This study analyzes the kinematic setting, the structural control and the volcanic productivity of 16 arcs. These arcs are characterized by predominant extensional, compressional, strike–slip or oblique motions. There is an overall coupling between the normal vs. parallel motions along the arc and those of the underlying slab. Therefore, the higher the trench-normal (or parallel) component of the subduction rate, the higher is the amount of arc-normal (or parallel) motion. This relation confirms that strain partitioning is, in general, feasible at many convergent settings, involving also the volcanic arc portion. The arc-normal motion may be characterized by extension or compression, as a function of the increase in the trench-normal convergence (or subduction) velocity. The lack of an evident relation between the subduction rate (or convergence rate) and the volcanic productivity of the arc is partly inconsistent with previous studies, which highlight a relation between the subduction rate and melt production below arcs. This discrepancy mainly suggests that different processes control the generation, rise and eruption of magma at different depths, varying the intrusive/extrusive ratio along arcs. The structure of the arc does not control the distribution of the volcanoes; however, it does control the volcanic output through different processes, even though regional or local extension (associated with strike–slip or compressive structures) is the ultimate requisite, in any setting. In general, the higher the amount of extension, the higher is the output rate along the arc.  相似文献   

Lethal and estrogenic effects of 4-nonylphenol in the cockle Cerastoderma glaucum   总被引：1，自引：1，他引：0  

Maria Gabriella Marin  Stefano Rigato  Francesco Ricciardi  Valerio Matozzo 《Marine pollution bulletin》2008,57(6-12):552

The lethal and sublethal effects of the xenoestrogen 4-nonylphenol (NP) were evaluated in the cockle Cerastoderma glaucum. In a 96-h lethality test, bivalves were exposed to 0, 0+ acetone, 0.19, 0.38, 0.75, 1.5 and 3.0 mg NP/l. The 96-h LC₅₀ value was 0.3 mg NP/l. No mortality was observed at 0.1 mg NP/l. The potential estrogenicity of NP was studied in both sexually undifferentiated (resting phase) and differentiated (pre-spawning phase) cockles, exposed for 7 and 14 days to 0, 0+ acetone, 0.0125, 0.025, 0.05, and 0.1 mg NP/l. Vitellogenin (Vg)-like protein levels were determined in both haemolymph and digestive gland by the alkali-labile phosphate (ALP) assay. In the resting phase, exposure for 7 days to 0.1 mg NP/l resulted in significant increases in ALP in both haemolymph and digestive gland, compared with controls. A significant increase was also observed in digestive gland of animals exposed to 0.0125 mg NP/l-exposed animals. After 14 days of exposure, haemolymph ALP levels were significantly increased in exposed animals at all NP concentrations tested, whereas no difference was recorded in digestive gland. In the pre-spawning phase, exposure for 7 days to NP significantly increased ALP levels in haemolymph from males exposed at all NP concentrations tested, whereas no significant variations were found in haemolymph from females. NP (0.05 and 0.1 mg/l) was also shown to increase ALP concentrations significantly in digestive gland of males, but not in those of females. Likewise, after 14 days’ exposure, ALP levels significantly increased in haemolymph from males only at 0.1 mg NP/l. Conversely, NP caused significant increases in ALP levels in digestive gland from both males (at all NP concentrations tested) and females (at 0.025 and 0.1 mg NP/l). These results demonstrate that NP induces Vg synthesis in C. glaucum. Interestingly, males were more responsive to NP than females.  相似文献   

Probabilistic seismic hazard model for Cairo,Egypt: estimates and uncertainties     

Ashraf Adly  Laurentiu Danciu  Donat Fäh  Valerio Poggi  Awad Omran  Awad Hassoup 《Bulletin of Earthquake Engineering》2018,16(12):5697-5733

A new seismic hazard model for Cairo, the capital city of Egypt is developed herein based on comprehensive consideration of uncertainties in various components of the probabilistic seismic hazard analysis. The proposed seismic hazard model is developed from an updated catalogue of historical and instrumental seismicity, geodetic strain rates derived from GPS-based velocity-field of the crust, and the geologic slip rates of active faults. The seismic source model consists of area sources and active faults characterised to forecast the seismic productivity in the region. Ground motion prediction models are selected to describe the expected ground motion at the sites of interest. The model accounts for inherent epistemic uncertainties of statistical earthquake recurrence; maximum magnitude; ground motion prediction models, and their propagation toward the obtained results. The proposed model is applied to a site-specific hazard analysis for Kottamiya, Rehab City and Zahraa-Madinat-Nasr (hereinafter referred to as Zahraa) to the East of Cairo (Egypt). The site-specific analysis accounts for the site response, through the parameterization of the sites in terms of average 30-m shear-wave velocity (Vs30). The present seismic hazard model can be considered as a reference model for earthquake risk mitigation and proper resilience planning.  相似文献   

Monitoring of structural systems by using frequency data     

Danilo Capecchi  Fabrizio Vestroni 《地震工程与结构动力学》1999,28(5):447-461

The present work evaluates the possibility of using dynamic data to assess structural integrity. It addresses the problem of understanding when it is sufficient to measure and use only natural frequencies, thus avoiding the need to measure modal shapes. The classic problem of detecting damage in beams, or beam assemblies, due to concentrated cracks, or damage spread over a structural member is dealt with. Damage is represented as a decrease in stiffness and linear behaviour before and after the event assumed to have caused damage is considered. Damage is restricted to a few unknown sections or elements, so that only the modification of few parameters of the system need to be determined. This study thus rejects assumptions unrelated to the physical aspects of the problem, in contrast to many papers on the subject. The amount of data to locate and quantify damage correctly is discussed; general considerations lead to the conclusion that a unique and reliable estimate of the damage can be obtained using only few additional frequency data with respect to the number of damaged zones. Continuous and discrete (finite element) models are examined. Finally the paper considers the applications to both analytical and experimental data of the procedure developed, which takes account of the peculiar characteristics of damage detection problem. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

Season‐based rainfall–runoff modelling using the probability‐distributed model (PDM) for large basins in southeastern Brazil          下载免费PDF全文

Rong Zhang  Luz Adriana Cuartas  Luiz Valerio de Castro Carvalho  Karinne Reis Deusdará Leal  Eduardo Mário Mendiondo  Narumi Abe  Stephen Birkinshaw  Guilherme Samprogna Mohor  Marcelo Enrique Seluchi  Carlos Afonso Nobre 《水文研究》2018,32(14):2217-2230

Southeastern Brazil is characterized by seasonal rainfall variability. This can have a great social, economic, and environmental impact due to both excessive and deficient water availability. During 2014 and 2015, the region experienced one of the most severe droughts since 1960. The resulting water crisis has seriously affected water supply to the metropolitan region of São Paulo and hydroelectric power generation throughout the entire country. This research considered the upstream basins of the southeastern Brazilian reservoirs Cantareira (2,279 km²; water supply) and Emborcação (29,076 km²), Três Marias (51,576 km²), Furnas (52,197 km²), and Mascarenhas (71,649 km²; hydropower) for hydrological modelling. It made the first attempt at configuring a season‐based probability‐distributed model (PDM‐CEMADEN) for simulating different hydrological processes during wet and dry seasons. The model successfully reproduced the intra‐annual and interannual variability of the upstream inflows during 1985–2015. The performance of the model was very satisfactory not only during the wet, dry, and transitional seasons separately but also during the whole period. The best performance was obtained for the upstream basin of Furnas, as it had the highest quality daily precipitation and potential evapotranspiration data. The Nash–Sutcliffe efficiency and logarithmic Nash–Sutcliffe efficiency were 0.92 and 0.93 for the calibration period 1984–2001, 0.87 and 0.88 for the validation period 2001–2010, and 0.93 and 0.90 for the validation period 2010–2015, respectively. Results indicated that during the wet season, the upstream basins have a larger capacity and variation of soil water storage, a larger soil water conductivity, and quicker surface water flow than during the dry season. The added complexity of configuring a season‐based PDM‐CEMADEN relative to the traditional model is well justified by its capacity to better reproduce initial conditions for hydrological forecasting and prediction. The PDM‐CEMADEN is a simple, efficient, and easy‐to‐use model, and it will facilitate early decision making and implement adaptation measures relating to disaster prevention for reservoirs with large‐sized upstream basins.  相似文献   

Stability of small fishing vessels in longitudinal waves     

M. A. S. Neves  N. A. Prez  L. Valerio 《Ocean Engineering》1999,26(12):347

The dynamic stability of fishing vessels in longitudinal regular waves is investigated, both analytically and experimentally. In particular, the influence of stern shape on the parametric stability of fishing vessels is studied. Vessels TS and RS have very similar main characteristics, but their sterns are different. Although their linear responses are comparable, both analytical and experimental investigations indicate substantial differences in their dynamic stability in longitudinal regular waves. Strong resonances are found for the vessel with the deep transom. The analytical method takes into consideration the effects of the heave and pitch motions and wave passage and shows good agreement with experimental results. Stability limits are obtained for different conditions and are used as an aid in the discussion of the results obtained in the tests when relevant parameters are changed, such as wave amplitude and frequency, metacentric height and roll damping moment.  相似文献   

Reproductive biology of the leatherjacket,Meuschenia scaber (Monacanthidae) (Forster 1801) in the Hauraki Gulf,New Zealand     

Valerio Visconti  Elizabeth D. L. Trip  Marc H. Griffiths  Kendall D. Clements 《新西兰海洋与淡水研究杂志》2018,52(1):82-99

The leatherjacket Meuschenia scaber is widely distributed in Australasian waters, and is a valued bycatch of inshore bottom trawl fisheries although little is known of its life history. Here, we describe the reproductive biology of the species based on 651 leatherjackets sampled in the Hauraki Gulf, New Zealand, between July 2014 and March 2016. The maximum total length (L_T) recorded for females and males were 320 and 315?mm, respectively, with both sexes present in all size classes. Monthly analysis of gonad condition revealed a clear spawning season from late austral winter to early summer (August–December), and histological analysis of the ovaries revealed that M. scaber is an indeterminate serial spawning gonochorist. The estimated sizes at sexual maturity (L₅₀) for females (189.9?mm L_T) and males (188.4?mm L_T) did not differ significantly. Relatively small testes, sexual dimorphism and underwater observation of nesting suggest that M. scaber is a paired spawner.  相似文献   

An ordered probit model for seismic intensity data     

Michela?CamelettiEmail author  Valerio?De Rubeis  Clarissa?Ferrari  Paola?Sbarra  Patrizia?Tosi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(7):1593-1602

Seismic intensity, measured through the Mercalli–Cancani–Sieberg (MCS) scale, provides an assessment of ground shaking level deduced from building damages, any natural environment changes and from any observed effects or feelings. Generally, moving away from the earthquake epicentre, the effects are lower but intensities may vary in space, as there could be areas that amplify or reduce the shaking depending on the earthquake source geometry, geological features and local factors. Currently, the Istituto Nazionale di Geofisica e Vulcanologia analyzes, for each seismic event, intensity data collected through the online macroseismic questionnaire available at the web-page www.haisentitoilterremoto.it. Questionnaire responses are aggregated at the municipality level and analyzed to obtain an intensity defined on an ordinal categorical scale. The main aim of this work is to model macroseismic attenuation and obtain an intensity prediction equation which describes the decay of macroseismic intensity as a function of the magnitude and distance from the hypocentre. To do this we employ an ordered probit model, assuming that the intensity response variable is related through the link probit function to some predictors. Differently from what it is commonly done in the macroseismic literature, this approach takes properly into account the qualitative and ordinal nature of the macroseismic intensity as defined on the MCS scale. Using Markov chain Monte Carlo methods, we estimate the posterior probability of the intensity at each site. Moreover, by comparing observed and estimated intensities we are able to detect anomalous areas in terms of residuals. This kind of information can be useful for a better assessment of seismic risk and for promoting effective policies to reduce major damages.  相似文献   

Hydrological regimes in different slope environments and implications on rainfall thresholds triggering shallow landslides     

Fusco  Francesco  Bordoni  Massimiliano  Tufano  Rita  Vivaldi  Valerio  Meisina  Claudia  Valentino  Roberto  Bittelli  Marco  De Vita  Pantaleone 《Natural Hazards》2022,114(1):907-939

Natural Hazards - Assessing hazard of rainfall-induced shallow landslides represents a challenge for the risk management of urbanized areas for which the setting up of early warning systems, based...  相似文献