Risk assessment of Tunguska-type airbursts   总被引：1，自引：1，他引：0  

Arnaud Mignan  Patricia Grossi  Robert Muir-Wood 《Natural Hazards》2011,56(3):869-880

The Tunguska airburst, which devastated a taiga forest over an area greater than 2,000 km² in a remote region of Central Siberia in 1908, is a classic example of extraterrestrial encounter discussed in the asteroid/comet impact hazard and risk assessment literature (e.g. Longo 2007; Carusi et al. 2007). Although it is generally agreed that the cosmic body caused damage by bursting in the air rather than through direct impact on the Earth’s surface, the Tunguska event is often referred to as an impact event. To the best of our knowledge, no detailed studies have been performed to quantify the risk of a similar-sized event over a populated region. We propose here a straightforward probabilistic risk model for Tunguska-type events over the continental United States and use established risk metrics to determine the property (buildings and contents) and human losses. We find an annual average property loss of ~USD 200,000/year, a rate of ~0.3 fatalities/year and ~1.0 injuries/year ranging from a factor 3 below and to a factor 3 above the indicated values when a reasonable rate uncertainty for Tunguska-type events is taken into account. We then illustrate the case of an extreme event over the New York metropolitan area. While we estimate that this “nightmare” scenario would lead to ~USD 1.5 trillion of property loss, ~3.9 millions of fatalities and ~4.7 millions of injuries, such event is almost impossible (occurrence once every ~30 million years) and should only be considered as an illustrative example.  相似文献   

On the reliability of the equivalent frame models: the case study of the permanently monitored Pizzoli’s town hall     

Degli Abbati  Stefania  Morandi  Paolo  Cattari  Serena  Spacone  Enrico 《Bulletin of Earthquake Engineering》2022,20(4):2187-2217

Bulletin of Earthquake Engineering - This paper presents the comparison of the results of modal and nonlinear analyses carried out on a 2-story masonry building with rigid diaphragms, inspired by...  相似文献   

HTLP metamorphism and fluid-fluxed melting during multistage anatexis of continental crust (N Sardinia,Italy)     

Leonardo Casini  Matteo Maino  Antonio Langone  Giacomo Oggiano  Stefania Corvò  Joan Reche Estrada  Montserrat Liesa 《Journal of Metamorphic Geology》2023,41(1):25-57

The Variscan high-grade metamorphic basement of northern Sardinia and southern Corsica record lower Carboniferous anatexis related to post-collisional decompression of the orogen. Migmatites exposed in the Punta Bianca locality (Italy) consist of quartz + biotite + plagioclase + K-feldspar orthogneisses, garnet and cordierite-bearing diatexite and metatexites, derived from metasediments. Field evidence, petrographic observations, ELA-ICP-MS zircon and monazite dating and pseudosection modelling suggest that anatexis was apparently episodic involving two main stages of partial melting. Using pseudosection modelling, we infer that the first stage of partial melting is in the upper amphibolite facies (~0.45 GPa at ~740°C). Cordierite overgrowths replacing sillimanite, combined with the composition of plagioclase and K-feldspar, suggest decompression followed cooling below the solidus at low pressures of ~0.3 GPa. The age of the first anatectic event is not precisely constrained because of extensive resetting of the isotopic systems during the second melting stage, yet few zircons preserve a lower Carboniferous age which is consistent with the regional dataset. This lower Carboniferous migmatitic fabric is offset by a network of pseudotachylyte-bearing faults suggestive of cooling to greenschist facies conditions. Garnet/cordierite-bearing diatexites incorporate fragments of pseudotachylite-bearing orthogneiss and metatexites. Pseudosection modelling indicates nearly isobaric re-heating up to ~750°C, followed by further cooling below the solidus. The inferred P–T path is consistent with decompression and cooling of the Variscan crust through post-collisional extension and collapse of the thickened orogenic crust, followed by nearly isobaric re-heating at low pressures (~0.3 GPa) yielding to a second melting stage under LP-HT conditions. U/Th-Pb monazite ages for diatexite migmatites indicate an upper bound of 310–316 Ma for the second melting stage, suggesting that the second melting stage is coincident with the regional phase of crustal shearing. The cause of the high geothermal gradient required for re-heating during the second melting stage is unknown but likely requires some heat source that was probably related to dissipation of mechanical work within crustal-scale shear zones. According to this interpretation, some upper Carboniferous peraluminous granite precursors of the Corsica–Sardinia Batholith could be the outcome rather than the cause of the late-Variscan high-T metamorphism.  相似文献   

Groundwater vulnerability maps derived from a time-dependent method using satellite scatterometer data     

Stefania Stevenazzi  Marco Masetti  Son V. Nghiem  Alessandro Sorichetta 《Hydrogeology Journal》2015,23(4):631-647

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Evolution of massive haloes in non-Gaussian scenarios     

M. Grossi  K. Dolag  E. Branchini  S. Matarrese  L. Moscardini 《Monthly notices of the Royal Astronomical Society》2007,382(3):1261-1267

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Guest editorial and overview     

Grossi  M. Tacconi  G. 《Oceanic Engineering, IEEE Journal of》1985,10(3):197-198

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One Year of Surface-Based Temperature Inversions at Dome C, Antarctica     

Ilaria Pietroni  Stefania Argentini  Igor Petenko 《Boundary-Layer Meteorology》2014,150(1):131-151

In 2005 the Study of Stable Boundary Layer Environment at Dome C (STABLEDC) experimental campaign was conducted at the plateau station of Concordia at Dome C, Antarctica. Temperature profiles measured with a microwave radiometer were used to study the characteristics of surface-based temperature inversions over the course of a year. Statistics of temperature profiles for every month are discussed; the difference between daytime and nocturnal cases observed during the summer months disappears during winter. Surface-based temperature inversions occurred in 70 % of the time during summer, and almost all of the time during winter. During winter the occurrence of warming events leads to a decrease in the temperature difference between the top and the base of the inversion (i.e. the inversion strength). The inversion strength maxima ranged between $3\,^{\circ }\mathrm{C}$ (December) and $35\,^{\circ }\mathrm{C}$ (August) corresponding to gradients of 0.1 and $0.3\,^{\circ }\mathrm{C}\, \mathrm{m}^{-1}$ , respectively. The average surface-based inversion height presents a daily cycle during the summer months with values up to 200 m in the morning hours, while it affects a layer always deeper than 100 m during the winter months. The relationships between inversion strength and the downward longwave radiative flux, absolute temperature, and wind speed are examined. The inversion strength decreases as the longwave radiation increases. A clear anti-correlation between inversion strength and near-surface temperature is evident throughout the year. During the winter, the largest inversion strength values were observed under low wind-speed conditions; in contrast, a clear dependence was not found during the summer.  相似文献   

Erratum to: Observed and Modelled Convective Mixing-Layer Height at Dome C,Antarctica     

Giampietro Casasanta  Ilaria Pietroni  Igor Petenko  Stefania Argentini 《Boundary-Layer Meteorology》2014,153(1):163-164

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Zonal jets and cyclone–anticyclone asymmetry in decaying rotating turbulence: laboratory experiments and numerical simulations     

Stefania Espa  Isabella Bordi  Thomas Frisius  Klaus Fraedrich  Antonio Cenedese  Alfonso Sutera 《地球物理与天体物理流体动力学》2013,107(6):557-573

The problem of zonal jet formation and cyclone–anticyclone asymmetry in decaying rotating turbulence is addressed using both laboratory experiments and numerical simulations with a high-resolution shallow water model in a spherical geometry. Experiments are performed at different Rossby and Froude numbers and applying a rigid wall as meridional boundary in the numerical scheme to mimic the experimental apparatus. The formation of a zonally banded flow pattern, i.e. meridionally confined easterly/westerly jets, has observed; both experimental and numerical results confirmed that this tendency is favoured by high-planetary vorticity gradients. Also, in the experiments characterized by large rotation speeds and small Rossby deformation radius, an initial symmetric distribution of relative vorticity is found to evolve towards a dominance of anticyclonic structures, indicating a breaking of the cyclone–anticyclone symmetry. This aspect has deepened by numerically analysing the sensitivity of the temporal variations of the asymmetry index with respect to the position of the meridional confinement as well as the effect of relaxing the divergence of the fluid (i.e. non-divergent case) to zero. Results suggested that experiments characterized by the higher rotation speed and the lower fluid thickness are better reproduced by a divergent model with a high-latitude meridional boundary.  相似文献   

Application of biomarkers for assessing the biological impact of dredged materials in the Mediterranean: the relationship between antioxidant responses and susceptibility to oxidative stress in the red mullet (Mullus barbatus)     

Regoli F  Pellegrini D  Winston GW  Gorbi S  Giuliani S  Virno-Lamberti C  Bompadre S 《Marine pollution bulletin》2002,44(9):912-922

In the period 1997-2000, approximately 1,800,000 m3 of material dredged from the Port of Leghorn was discharged into a sea dumping site located 14 miles from the coast. The red mullet (Mullus barbatus) was used as a bioindicator species for monitoring the biological impact of these discharges on a geographical and temporal scale. Organisms were sampled over three years (1998-2000) at different stations and several biomarkers, both of exposure and effect, were analyzed. Bioavailability of specific classes of pollutants was evaluated by analyzing levels of metallothioneins, the activity of cytochrome P450 1A (CYPIA) and of glutathione S-transferases. Among biomarkers of effect, special attention was paid to the balance between prooxidant challenge and antioxidant defenses, and to the appearance of damage caused by oxidative stress. The analyses of the main components of the antioxidant system included superoxide dismutase, catalase, glutathione peroxidases, glutathione reductase, glyoxalase I and II, and total glutathione. These data were integrated with the measurement of total oxyradical scavenging capacity (TOSC) as an indication of the overall biological resistance to toxicity of different forms of oxyradicals (peroxyl radicals, hydroxyl radicals and peroxynitrite). Results indicated a biological impact in organisms sampled near the disposal site; the impact was particularly evident during 1999 and mainly related to organic chemicals such as PAH. Exposure to these pollutants also caused variations in the levels and activity of several antioxidants. The analysis of TOSC, however, revealed that the overall capacity of specific tissues of organisms to absorb various oxidants was not seriously compromised when challenged with increased prooxidant pressures. Variations of single antioxidants were useful in revealing early warning "biological responses", while integration with TOSC analyses indicated if such changes also reflect a more integrated and functional "biological effect" with possible consequences at the organisms level. The red mullet appears to be a useful sentinel species for a biomarker approach to monitoring impact caused by dredged materials.  相似文献