Slope instability induced by volcano-tectonics as an additional source of hazard in active volcanic areas: the case of Ischia island (Italy)   总被引：1，自引：0，他引：1  

Marta Della Seta  Enrica Marotta  Giovanni Orsi  Sandro de Vita  Fabio Sansivero  Paola Fredi 《Bulletin of Volcanology》2012,74(1):79-106

Ischia is an active volcanic island in the Gulf of Naples whose history has been dominated by a caldera-forming eruption (ca. 55 ka) and resurgence phenomena that have affected the caldera floor and generated a net uplift of about 900 m since 33 ka. The results of new geomorphological, stratigraphical and textural investigations of the products of gravitational movements triggered by volcano-tectonic events have been combined with the information arising from a reinterpretation of historical chronicles on natural phenomena such as earthquakes, ground deformation, gravitational movements and volcanic eruptions. The combined interpretation of all these data shows that gravitational movements, coeval to volcanic activity and uplift events related to the long-lasting resurgence, have affected the highly fractured marginal portions of the most uplifted Mt. Epomeo blocks. Such movements, mostly occurring since 3 ka, include debris avalanches; large debris flows (lahars); smaller mass movements (rock falls, slumps, debris and rock slides, and small debris flows); and deep-seated gravitational slope deformation. The occurrence of submarine deposits linked with subaerial deposits of the most voluminous mass movements clearly shows that the debris avalanches impacted on the sea. The obtained results corroborate the hypothesis that the behaviour of the Ischia volcano is based on an intimate interplay among magmatism, resurgence dynamics, fault generation, seismicity, slope oversteepening and instability, and eruptions. They also highlight that volcano-tectonically triggered mass movements are a potentially hazardous phenomena that have to be taken into account in any attempt to assess volcanic and related hazards at Ischia. Furthermore, the largest mass movements could also flow into the sea, generating tsunami waves that could impact on the island’s coast as well as on the neighbouring and densely inhabited coast of the Neapolitan area.  相似文献   

Displacement-based design of steel moment resisting frames with partially-restrained beam-to-column joints     

R. Roldán  T. J. Sullivan  G. Della Corte 《Bulletin of Earthquake Engineering》2016,14(4):1017-1046

This article presents a method for the direct displacement-based design of steel moment resisting frames, with specific consideration of beam-to-column joint characteristics. The method can be used for steel frames having any type of beam-to-column joints, from rigid and full-strength to semi-rigid and partial-strength. The plastic rotation capacity of the joints is explicitly taken into account within the performance criteria for the design. To assess the accuracy of the method in controlling performance, case study structures were first designed and subsequently analysed using non-linear dynamic analysis with a set of real accelerograms. For all cases, the mean of peak inter-storey drift demands and the mean of peak plastic rotation demands on joints were controlled in accordance with the limits set during design. The results obtained demonstrate that the proposed method is appropriate for the performance-based seismic design of steel moment resisting frames with different joint typologies.  相似文献   

Synthetic ANaB(Na x Li1 − x Mg1)CMg5Si8O22(OH)2 (with x = 0.6, 0.2 and 0) P21/m amphiboles at high pressure: a synchrotron infrared study     

Gianluca Iezzi  Zhenxian Liu  Giancarlo Della Ventura 《Physics and Chemistry of Minerals》2009,36(6):343-354

The high-pressure behavior of three synthetic amphiboles crystallized with space group P2₁/m at room conditions in the system Li₂O–Na₂O–MgO–SiO₂–H₂O has been studied by in situ synchrotron infrared absorption spectroscopy. The amphiboles have compositions ^ANa ^B(Na _x Li_1 − x Mg₁) ^CMg₅ Si₈ O₂₂(OH)₂ with x = 0.6, 0.2 and 0.0, respectively. The high-P experiments up to 32 GPa were carried out on the U2A beamline at Brookhaven National Laboratory (NY, USA) using a diamond anvil cell under non-hydrostatic or quasi-hydrostatic conditions. The two most intense absorption bands in the OH-stretching infrared spectra can be assigned to two non-equivalent O–H dipoles in the P2₁/m structure, bonded to the same local environment ^M1M3Mg₃–OH–^ANa, and pointing toward two differently kinked tetrahedral rings. In all samples these bands progressively merge to give a unique symmetrical absorption with increasing pressure, suggesting a change in symmetry from P2₁/m to C2/m. The pressure at which the transition occurs appears to be linearly correlated to the aggregate B-site dimension. The infrared spectra collected for amphibole ^B(Na_0.2Li_0.8Mg₁) in the frequency range 50 to 1,400 cm⁻¹ also show a series of changes with increasing pressure. The data reported here support the inference of Iezzi et al. (Am Miner 91:479–482, 2006a) regarding a new high-pressure amphibole polymorph.  相似文献   

(137)Cs baseline levels in the Mediterranean and Black Sea: a cross-basin survey of the CIESM Mediterranean Mussel Watch programme     

Thébault H  Rodriguez Y Baena AM  Andral B  Barisic D  Albaladejo JB  Bologa AS  Boudjenoun R  Delfanti R  Egorov VN  El Khoukhi T  Florou H  Kniewald G  Noureddine A  Patrascu V  Pham MK  Scarpato A  Stokozov NA  Topcuoglu S  Warnau M 《Marine pollution bulletin》2008,57(6-12):801-806

The common mussel Mytilus galloprovincialis was selected as unique biomonitor species to implement a regional monitoring programme, the CIESM Mediterranean Mussel Watch (MMW), in the Mediterranean and Black Seas. As of today, and upon standardization of the methodological approach, the MMW Network has been able to quantify (137)Cs levels in mussels from 60 coastal stations and to produce the first distribution map of this artificial radionuclide at the scale of the entire Mediterranean and Black Seas. While measured (137)Cs levels were found to be very low (usually < 1 Bq kg(-1) wet wt) (137)Cs activity concentrations in the Black Sea and North Aegean Sea were up to two orders of magnitude higher than those in the western Mediterranean Basin. Such effects, far from representing a threat to human populations or the environment, reflect a persistent signature of the Chernobyl fallout in this area.  相似文献   

The exceptionally bright Type Ib supernova 1991D     

S. Benetti  D. Branch  M. Turatto  E. Cappellaro  E. Baron  L. Zampieri  M. Della Valle  A. Pastorello 《Monthly notices of the Royal Astronomical Society》2002,336(1):91-96

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Observations of the long-period variable star Y Ori     

N. D. Melikyan  R. Sh. Natsvlishvili  M. Della Valle 《Astrophysics》1988,28(2):193-197

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Aquifer-induced Seismicity in the Central Apennines (Italy)     

F. Bella  P. F. Biagi  M. Caputo  E. Cozzi  G. Della Monica  A. Ermini  W. Plastino  V. Sgrigna 《Pure and Applied Geophysics》1998,153(1):179-194

—The Gran Sasso chain (Central Apennines, Italy) contains one of the largest aquifers of Central Italy. From 1970–1986 the massif was tunnelled through in order to build up a highway and an international underground laboratory for nuclear physics research. These works have strongly modified the hydrogeological situation of the chain, as shown by the decrease in flow rate that occurred in many springs located at the border of the carbonatic structure, along the boundary between the permeable limestone of the massif and the surrounding aquicludes. The analysis of the seismicity (M≥ 3.0) that occurred in the Gran Sasso area from 1956 to 1995 suggests that after the tunnelling works both the number of earthquakes has increased and epicenters have migrated, gathering at the northwestern border zone. The foremost events which occurred in this zone in recent years took place on May 5, 1992 (M = 3.1), August 25, 1992 (M = 3.9) and March 13, 1994 (M = 3.5). The flow rate data of four springs and water level data of an underground karst pool located at the border of the carbonatic structure of the massif show clear anomalies before the occurrence of the quoted earthquakes. Regardless, these anomalies can be explained by the rapid melting of the thick mantle of snow on the Gran Sasso chain, due to sudden increases of mean temperatures. In this paper we present and discuss the possibility that the quoted earthquakes are induced by the irregular variations of the Gran Sasso aquifer, evidenced by the quoted anomalies in the flow rate and water level.  相似文献   

Globular cluster calibration of the peak brightness of the Type Ia supernova 1992A and the value of H₀     

M. Della Valle  M. Kissler-Patig  J. Danziger  & J. Storm 《Monthly notices of the Royal Astronomical Society》1998,299(1):267-276

We have determined the absolute magnitude at maximum light of SN 1992A by using the turnover magnitude of the globular cluster luminosity function of its parent galaxy, NGC 1380. A recalibration of the peak of the turnover magnitude of the Milky Way clusters using the latest Hipparcos results has been made with an assessment of the complete random and systematic error budget. The following results emerge: a distance to NGC 1380 of 18.6 ± 1.4 Mpc, corresponding to ( m  −  M )  31.35 ± 0.16, and an absolute magnitude of SN 1992A at maximum of M _B (max)  −18.79 ± 0.16. Taken at face value, SN 1992A seems to be more than half a magnitude fainter than the other SNe Ia for which accurate distances exist. We discuss the implications of this result and present possible explanations. We also discuss the Phillips relationship between rate of decline and the absolute magnitude at maximum, on the basis of nine SNe Ia, the individual distances of which have been obtained with Cepheids and the globular cluster luminosity function. The new calibration of this relationship, applied to the most distant SNe of the Calan–Tololo survey, yields H ₀ = 62 ± 6 km s⁻¹ Mpc⁻¹.  相似文献   

Investigating possible links between the North Atlantic Oscillation and rainfall variability in Marrakech (Morocco)     

Imen?TurkiEmail author  Benoit?Laignel  Noureddine?Laftouhi  Zeneddine?Nouaceur  Zineb?Zamrane 《Arabian Journal of Geosciences》2016,9(3):243

Eighty-two-year rainfall time series have been studied together with climatic patterns of NAO using classical statistical methods. Then, the wavelet approach has been applied to show annual (1 year (1y)) and inter-annual (2–4 years (2-4y), 5–8 years (5-8y), and 8–16 years (8-16y)) modes distributed following four major discontinuities: 1945, 1960, 1975, and 1995. The 1y, 2-4y, and 5-8y powers show high energy during the wet period 1922–1930 and a low one in 1928–1938. After 1945, the annual mode highlights a high energy while the inter-annual modes present low energy. Between 1975 and 1995, powerful modes of 1 and 2–4 years are identified with low power of 5-8y and 8-16y modes. Since 1995, the low power of 5–8y decreases, while the 8-16y mode emphasizes a high variability. The coherence between NAO and Marrakech precipitation is strongly defined for low frequencies with a total contribution of 75 %. This coherence is in phase in the beginning and presents out phase signs since 1945. The change of phase can be associated to a decreasing of coherence especially around 1990. This finding is useful to understand the relationship between the hydrological variability and NAO climate patterns in the southern side of the Mediterranean Sea.  相似文献   

Speciation and diffusion profiles of H2O in water-poor beryl: comparison with cordierite     

G. Della Ventura  F. Radica  F. Bellatreccia  C. Freda  M. Cestelli Guidi 《Physics and Chemistry of Minerals》2015,42(9):735-745

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