High precision tilt observation at Mt. Etna Volcano,Italy     

Angelo Ferro  Salvatore Gambino  Stefano Panepinto  Giuseppe Falzone  Giuseppe Laudani  Bernard Ducarme 《Acta Geophysica》2011,59(3):618-632

In 2007–2008, we installed on Mt. Etna two deep tilt stations using high resolution, self-leveling instruments. These installations are a result of accurate instrument tests, site selection, drilling and sensor positioning that has allowed detecting variations related to the principal diurnal and semidiurnal tides for first time on Mt. Etna using tilt data.  相似文献   

Hysteretic behaviour of bracing‐type pure aluminium shear panels by experimental tests     

Gianfranco De Matteis  Giuseppe Brando  Federico M. Mazzolani 《地震工程与结构动力学》2011,40(10):1143-1162

This paper deals with experimental tests aimed at assessing the structural performance of pure aluminium shear panels to be employed as passive energy dissipation devices with a bracing type configuration. The AW1050 A H24 is adopted as the basic material. It is an aluminium alloy with a negligible content of impurity, allowing it to be considered as a pure aluminium. In this paper, the results of four full‐scale 5thinspacemm thick multi‐stiffened square‐shaped specimens tested under cyclic diagonal loads and characterized by different slenderness ratios are presented. In order to determine the main resisting mechanisms for different shear strain demands, a careful examination of the experimental evidences is provided. Then, the global performance of tested shear panels is evaluated by the comparison of the obtained hysteretic responses, evidencing the effect of the plate slenderness on the energy dissipation capacity. Finally, a suitable analytical model, which could be useful to implement global dynamic non‐linear analysis, is set up in order to interpret the behaviour of shear panels for which the development of premature buckling phenomena is completely inhibited. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Mind the gap: Addressing the shortcomings of marine protected areas through large scale marine spatial planning   总被引：1，自引：0，他引：1  

Tundi Agardy  Giuseppe Notarbartolo di Sciara  Patrick Christie 《Marine Policy》2011

A blind faith in the ability of MPAs to counteract loss of biodiversity is fraught with risk, especially when MPAs are poorly planned and when the consequences of establishing MPAs are not adequately thought out. MPA shortcomings are categorized as one of five main types: (1) MPAs that by virtue of their small size or poor design are ecologically insufficient; (2) inappropriately planned or managed MPAs; (3) MPAs that fail due to the degradation of the unprotected surrounding ecosystems; (4) MPAs that do more harm than good due to displacement and unintended consequences of management; and (5) MPAs that create a dangerous illusion of protection when in fact no protection is occurring. A strategic alternative, which fully utilizes the strengths of the MPA tool while avoiding the pitfalls, can overcome these shortcomings: integrating marine protected area planning in broader marine spatial planning and ocean zoning efforts.  相似文献   

Raw Materials for Archaeological Pottery from the Campania Region of Italy: A Petrophysical Characterization     

Alberto De Bonis  Celestino Grifa  Giuseppe Cultrone  Pantaleone De Vita  Alessio Langella  Vincenzo Morra 《Geoarchaeology》2013,28(5):478-503

We performed petrophysical analyses on 34 clayey samples of different geological origin within the Campania region of Italy in order to determine possible sources of raw materials used to produce ancient pottery. Possible raw material sources can be grouped into high‐CaO clays (HCC) and low‐CaO clays (LCC). HCC are mainly represented by more recent (Miocene‐Pleistocene) basinal sediments whereas LCC tend to be associated with basinal, alluvial, and pyroclastic deposits. A chemical comparison between clayey raw materials, modern ceramic replicas, and Campanian archaeological ceramics of several typologies (common ware, cooking ware, fine tableware, amphorae, and bricks) from 8th century B.C. to the Middle Ages (a total of 350 ceramic samples) indicates that HCC were extensively used for common wares and that these were either mixed with temper or levigated. In contrast, most of the LCC were used for the production of cookware. We also analyzed the technological potential of the sampled raw materials, taking into consideration their actual and possible uses. We observed that most HCC deposits were well suited for tableware and amphorae, whereas LCC were better for cookware and some fine tableware.  相似文献   

The Taraklı Flysch in the Boyali area (Sakarya Terrane,northern Turkey): Implications for the tectonic history of the IntraPontide suture zone     

Rita Catanzariti  Alessandro Ellero  Mehmet Cemal Göncüoglu  Michele Marroni  Giuseppe Ottria  Luca Pandolfi 《Comptes Rendus Geoscience》2013,345(11-12):454-461

In the Boyal? area, northern Turkey, the tectonic units of the ?stanbul–Zonguldak Terrane and the IntraPontide suture zone are thrust over the deposits at the top of the Sakarya Terrane, known as Tarakl? Flysch. It consists of Early Maastrichtian–Middle Paleocene turbidite and mass-gravity deposits, whose source mainly corresponds to the ?stanbul–Zonguldak Terrane, and, with a lesser extent, to the IntraPontide suture zone. These deposits were sedimented in a foredeep basin developed during the convergence between Sakarya and Eurasian continental microplates. In the Late Paleocene–Early Eocene time span, the Tarakl? Flysch was deformed (D1 phase) during the closure of the foredeep basin. In the Miocene time, the strike-slip tectonics (D2 phase) related to the North-Anatolian fault produced further deformations of the Tarakl? Flysch.  相似文献   

7000 years of paleostorm activity in the NW Mediterranean Sea in response to Holocene climate events     

Pierre Sabatier  Laurent Dezileau  Christophe Colin  Louis Briqueu  Frédéric Bouchette  Philippe Martinez  Giuseppe Siani  Olivier Raynal  Ulrich Von Grafenstein 《Quaternary Research》2012,77(1):1-11

A high-resolution record of paleostorm events along the French Mediterranean coast over the past 7000 years was established from a lagoonal sediment core in the Gulf of Lions. Integrating grain size, faunal analysis, clay mineralogy and geochemistry data with a chronology derived from radiocarbon dating, we recorded seven periods of increased storm activity at 6300–6100, 5650–5400, 4400–4050, 3650–3200, 2800–2600, 1950–1400 and 400–50 cal yr BP (in the Little Ice Age). In contrast, our results show that the Medieval Climate Anomaly (1150–650 cal yr BP) was characterised by low storm activity.The evidence for high storm activity in the NW Mediterranean Sea is in agreement with the changes in coastal hydrodynamics observed over the Eastern North Atlantic and seems to correspond to Holocene cooling in the North Atlantic. Periods of low SSTs there may have led to a stronger meridional temperature gradient and a southward migration of the westerlies. We hypothesise that the increase in storm activity during Holocene cold events over the North Atlantic and Mediterranean regions was probably due to an increase in the thermal gradient that led to an enhanced lower tropospheric baroclinicity over a large Central Atlantic–European domain.  相似文献   

Geodetic techniques applied to the study of the Etna volcano area (Italy)     

Santo La Delfa  Monia Negusini  Sabrina Di Martino  Giuseppe Patanè 《International Journal of Earth Sciences》2012,101(4):1065-1075

Volcanic behaviour of Mt. Etna is due to the complex interaction between both the local and the regional stress field involving the eastern Sicily. Eruptions could trigger (be triggered?) during crust extension and/or compression, which are strictly linked with the dynamics of the lower mantle. In this study, very long baseline interferometry (VLBI) space geodesy technique has been used in order to study Etna volcano’s activity by means of the crustal deformations between Noto and Matera (located on the African and the Eurasian Plates, respectively). By analysing VLBI data, we obtained the behaviour of the baseline which crosses the Etnean area, from 1990 December to 2003 March, representing the time variations of the distance between the two geodetic stations; the linear trend of the baseline shows a general increasing, pointing out an extension of the crust between them. A detailed analysis of the Noto-Matera baseline allows the identification of three parts of the VLBI curve in the considered period. In the first part of the curve (from 20/12/90 to 09/02/94), VLBI data are rather poor and therefore no reliable consideration about correlation between crust movements and volcanic and seismicity activity has been made. In the second part of the curve (from 09/02/94 to 04/09/00), VLBI data are more frequent and show slightly fluctuations in the distance. Increasing in the extension and compression were observed in the central and in the final part of this period. In the third period (from 04/09/00 to 25/03/03), VLBI data are very sparse even if the time series was quite long; therefore, to fill gaps in the information, we analysed global positioning system (GPS) data. GPS technique performs continuous observations, and we were able to highlight both extensions and compressions in detail. Comparisons between the trend of Noto-Matera baseline length variations, volcanic activity and seismicity in the Etna area show the complexity of the development over time and space of the phenomenology determined by a deep cause which can be traced, in our opinion, to the interaction between the asthenospheric mantle, deep crust and surface crust. Therefore, we state that crustal distension and compression are determined by the lower pulsating mantle.  相似文献   

Damping‐adjusted combination rule for the response spectrum analysis of base‐isolated buildings     

Giuseppe Muscolino  Alessandro Palmeri  Claudia Versaci 《地震工程与结构动力学》2013,42(2):163-182

The classical response spectrum method continues to be the most popular approach for designing base‐isolated buildings, therefore avoiding computationally expensive nonlinear time‐history analyses. In this framework, a new method for the seismic analysis and design of building structures with base isolation system (BIS) is formulated and numerically validated, which enables one to overcome the main shortcomings of existing techniques based on the response spectrum method. The main advantages are the following: first, reduced computational effort with respect to an exact complex‐valued modal analysis, which is obtained through a transformation of coordinates in two stages, both involving real‐valued eigenproblems; second, effective representation of the damping, which is pursued by consistently defining different viscous damping ratios for the modes of vibration of the coupled BIS‐superstructure dynamic system; and third, ease of use, because a convenient reinterpretation of the combination coefficients leads to a novel damping‐adjusted combination rule, in which just a single response spectrum is required for the reference value of the viscous damping ratio. The proposed approach is specifically intended for design situations where (i) the dynamic behaviour of seismic isolators can be linearised and (ii) effects of nonproportional damping, as measured by modal coupling indexes, are negligible in the BIS‐superstructure assembly. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Effect of stratification on the frequency of bounded Rossby modes over a non-flat bottom     

Giuseppe Colantuono  Robert Erdélyi  Michael S. Ruderman 《地球物理与天体物理流体动力学》2013,107(5):541-563

This work attempts to express and analyze the challenges, induced by stratification, affecting the Rossby-topographic eigenmodes of a closed domain with a general uneven bottom of arbitrary shape filled with a uniform fluid in the unperturbed configuration. The modified eigenmodes have been computed analytically: stratification is introduced in the mathematical form of a perturbation of a homogeneous fluid over a non-flat bottom. The eigenmodes lose their barotropic character and differences appear in the dynamical fields (velocity and pressure) from upper to lower layer, as expected. Expressions for the baroclinic and ageostrophic velocity components due to the perturbation are given. The analysis is carried out in the frame of linear shallow water approximation. All terms have been retained apart from nonlinear advection in the governing equations. We find that the frequencies of the eigenmodes change; an analytical expression of frequency correction as a function of layer density difference and interface depth is found. Initial results for some elementary geometrical settings with a waveguide bottom are determined and expressed in a concise, easily readable closed form. The results obtained in the shallow water approximation are expanded in series with respect to the Rossby number. Next, they are compared with the frequency correction obtained in an alternative framework in which the quasi-geostrophic approximation is used, and a purely baroclinic perturbation is imposed from the outset as the result of the introduction of stratification in the otherwise homogeneous fluid. In this scenario, reduced gravity and the ratio of upper to lower layer depth are, in turn, used as the expansion parameters in lieu of the Rossby number.  相似文献   

Location Performance and Detection Threshold of the Spanish National Seismic Network     

Antonino D’Alessandro  José Badal  Giuseppe D’Anna  Dimitris Papanastassiou  Ioannis Baskoutas  Nurcan M. Özel 《Pure and Applied Geophysics》2013,170(11):1859-1880

Spain is a low-to-moderate seismicity area with relatively low seismic hazard. However, several strong shallow earthquakes have shaken the country causing casualties and extensive damage. Regional seismicity is monitored and surveyed by means of the Spanish National Seismic Network, maintenance and control of which are entrusted to the Instituto Geográfico Nacional. This array currently comprises 120 seismic stations distributed throughout Spanish territory (mainland and islands). Basically, we are interested in checking the noise conditions, reliability, and seismic detection capability of the Spanish network by analyzing the background noise level affecting the array stations, errors in hypocentral location, and detection threshold, which provides knowledge about network performance. It also enables testing of the suitability of the velocity model used in the routine process of earthquake location. To perform this study we use a method that relies on P and S wave travel times, which are computed by simulation of seismic rays from virtual seismic sources placed at the nodes of a regular grid covering the study area. Given the characteristics of the seismicity of Spain, we drew maps for M _L magnitudes 2.0, 2.5, and 3.0, at a focal depth of 10 km and a confidence level 95 %. The results relate to the number of stations involved in the hypocentral location process, how these stations are distributed spatially, and the uncertainties of focal data (errors in origin time, longitude, latitude, and depth). To assess the extent to which principal seismogenic areas are well monitored by the network, we estimated the average error in the location of a seismic source from the semiaxes of the ellipsoid of confidence by calculating the radius of the equivalent sphere. Finally, the detection threshold was determined as the magnitude of the smallest seismic event detected at least by four stations. The northwest of the peninsula, the Pyrenees, especially the westernmost segment, the Betic Cordillera, and Tenerife Island are the best-monitored zones. Origin time and focal depth are data that are far from being constrained by regional events. The two Iberian areas with moderate seismicity and the highest seismic hazard, the Pyrenees and Betic Cordillera, and the northwestern quadrant of the peninsula, are the areas wherein the focus of an earthquake is determined with an approximate error of 3 km. For M _L 2.5 and M _L 3.0 this error is common for almost the whole peninsula and the Canary Islands. In general, errors in epicenter latitude and longitude are small for near-surface earthquakes, increasing gradually as the depth increases, but remaining close to 5 km even at a depth of 60 km. The hypocentral depth seems to be well constrained to a depth of 40 km beneath the zones with the highest density of stations, with an error of less than 5 km. The M _L magnitude detection threshold of the network is approximately 2.0 for most of Spain and still less, almost 1.0, for the western sector of the Pyrenean region and the Canary Islands.  相似文献