Impact of explosive volcanic eruptions around Vesuvius: a story of resilience in Roman time     

Claudio Scarpati  Annamaria Perrotta  Girolamo Ferdinando De Simone 《Bulletin of Volcanology》2016,78(3):21

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Lava discharge during Etna's January 2011 fire fountain tracked using MSG-SEVIRI     

Mathieu Gouhier  Andrew Harris  Sonia Calvari  Philippe Labazuy  Yannick Guéhenneux  Franck Donnadieu  Sébastien Valade 《Bulletin of Volcanology》2012,74(4):787-793

Etna's January 2011 eruption provided an excellent opportunity to test the ability of Meteosat Second Generation satellite's Spinning Enhanced Visible and InfraRed Imager (SEVIRI) sensor to track a short-lived effusive event. The presence of lava fountaining, the rapid expansion of lava flows, and the complexity of the resulting flow field make such events difficult to track from the ground. During the Etna's January 2011 eruption, we were able to use thermal data collected by SEVIRI every 15 min to generate a time series of the syn-eruptive heat flux. Lava discharge waxed over a ~1-h period to reach a peak that was first masked from the satellite view by a cold tephra plume and then was of sufficient intensity to saturate the 3.9-μm channel. Both problems made it impossible to estimate time-averaged lava discharge rates using the syn-eruptive heat flux curve. Therefore, through integration of data obtained by ground-based Doppler radar and thermal cameras, as well as ancillary satellite data (from Moderate Resolution Imaging Spectrometer and Advanced Very High Resolution Radiometer), we developed a method that allowed us to identify the point at which effusion stagnated, to allow definition of a lava cooling curve. This allowed retrieval of a lava volume of ~1.2 × 10⁶ m³, which, if emitted for 5 h, was erupted at a mean output rate of ~70 m³ s⁻¹. The lava volume estimated using the cooling curve method is found to be similar to the values inferred from field measurements.  相似文献   

Monte Carlo method applied to modeling copper transport in river sediments   总被引：2，自引：2，他引：0  

Marcela Z. Corazza  Taufik Abr?o  Fábio Grandis Lepri  Sonia M. N. Gimenez  Elisabeth Oliveira  Maria Josefa Santos 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(8):1063-1079

Monte Carlo simulation (MCS) methodology has been applied to explain the variability of parameters for pollutant transport and fate modeling. In this study, the MCS method was used to evaluate the transport and fate of copper in the sediment of the Tibagi River sub-basin tributaries, Southern Brazil. The statistical distribution of the variables was described by a dataset obtained for copper concentration using sequential extraction, organic matter (OM) amount, and pH. The proposed stochastic spatial model for the copper transport in the river sediment was discussed and implemented by the MCS technique using the MatLab 7.3? mathematical software tool. In order to test some hypotheses, the sediment and the water column in the river ecosystem were considered as compartments. The proposed stochastic spatial model makes it possible to predict copper mobility and associated risks as a function of the organic matter input into aquatic systems. The metal mobility can increase with the OM posing a rising environmental risk.  相似文献   

Seismic response of buried metro tunnels by a hybrid FDM-BEM approach     

George D. Manolis  Sonia L. Parvanova  Konstantina Makra  Petia S. Dineva 《Bulletin of Earthquake Engineering》2015,13(7):1953-1977

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Chemical and isotopic characterization of hydrocarbon gas traces in porewater of very low permeability rocks: The example of the Callovo-Oxfordian argillites of the eastern part of the Paris Basin     

Alain Prinzhofer  Jean Pierre Girard  Stphane Buschaert  Yvon Huiban  Sonia Noirez 《Chemical Geology》2009,260(3-4):269-277

A methodology has been developed to determine chemical and carbon isotopic compositions of trace amounts of hydrocarbon gas compounds (methane, ethane, propane, iso- and normal-butane) present as dissolved compounds in the porewater of the low permeability Callovo-Oxfordian argillites in eastern Paris Basin, France. Results indicate that the studied hydrocarbons contain significant amounts of ethane, butane and propane, in addition to methane. Carbon isotopic compositions reflect primarily thermogenic origin (thermal cracking of organic matter), and lack of any significant biodegradation. Because temperature did not exceed 50 °C in the studied argillites, investigated hydrocarbons must have originated in hotter/deeper organic-bearing formations, possibly Stephanian coals. Data supports the predominance of high maturity thermogenic gas in the upper part of the Callovo-Oxfordian, and low maturity thermogenic gas mixed with minor bacterially produced methane in the lower part of the formation. A mixing between three end-member gases models quite well the data: one thermogenic gas with a low maturity (42% methane, with a δ¹³C of − 53‰), a gas with higher maturity (55% methane, with a δ¹³C of − 47‰) and a bacterial gas (99.45% methane, with a δ¹³C of − 80‰). This study illustrates that migration of hydrocarbon gases can take place in rocks with very low permeability and porosity, such as compacted mudrocks, given enough time. It further suggests that the studied fluid migration and transfer in aquitards would help characterization and understanding of fluid movements in sedimentary basins, as a complement to studies focused on water aquifers and hydrocarbon reservoirs. Chemical and isotopic composition of dissolved hydrocarbons in porewater can be used as natural tracers of fluid circulation in sedimentary basins, in addition to more conventional tracers.  相似文献   

Marine pollution control in Europe: Regional approaches, 1972–80     

Sonia Boehmer-Christiansen 《Marine Policy》1984,8(1):44-55

This article evaluates the effectiveness of four regional pollution agreements concluded during the 1970s: The Bonn Agreement, the Oslo Convention, the Paris Convention and the Helsinki Convention. The treaties are described and their implementation to 1980 outlined. The issue of EEC participation in environmental protection in Europe is analysed and problems of overlap with the treaties under discussion are pointed out. A major conclusion of the article is the need for more implementation research to properly assess the effectiveness of such regional agreements.  相似文献   

A multi-disciplinary study of the 2002–03 Etna eruption: insights into a complex plumbing system     

Daniele Andronico  Stefano Branca  Sonia Calvari  Michael Burton  Tommaso Caltabiano  Rosa Anna Corsaro  Paola Del Carlo  Gaetano Garfì  Luigi Lodato  Lusia Miraglia  Filippo Murè  Marco Neri  Emilio Pecora  Massimo Pompilio  Guiseppe Salerno  Letizia Spampinato 《Bulletin of Volcanology》2005,67(4):314-330

The 2002–03 Mt Etna flank eruption began on 26 October 2002 and finished on 28 January 2003, after three months of continuous explosive activity and discontinuous lava flow output. The eruption involved the opening of eruptive fissures on the NE and S flanks of the volcano, with lava flow output and fire fountaining until 5 November. After this date, the eruption continued exclusively on the S flank, with continuous explosive activity and lava flows active between 13 November and 28 January 2003. Multi-disciplinary data collected during the eruption (petrology, analyses of ash components, gas geochemistry, field surveys, thermal mapping and structural surveys) allowed us to analyse the dynamics of the eruption. The eruption was triggered either by (i) accumulation and eventual ascent of magma from depth or (ii) depressurisation of the edifice due to spreading of the eastern flank of the volcano. The extraordinary explosivity makes the 2002–03 eruption a unique event in the last 300 years, comparable only with La Montagnola 1763 and the 2001 Lower Vents eruptions. A notable feature of the eruption was also the simultaneous effusion of lavas with different composition and emplacement features. Magma erupted from the NE fissure represented the partially degassed magma fraction normally residing within the central conduits and the shallow plumbing system. The magma that erupted from the S fissure was the relatively undegassed, volatile-rich, buoyant fraction which drained the deep feeding system, bypassing the central conduits. This is typical of most Etnean eccentric eruptions. We believe that there is a high probability that Mount Etna has entered a new eruptive phase, with magma being supplied to a deep reservoir independent from the central conduit, that could periodically produce sufficient overpressure to propagate a dyke to the surface and generate further flank eruptions.Editorial responsibility: J. Donnelly-Nolan  相似文献   

The Impact of Erosion on Soil Productivity—An Experimental Design Applied in São Paulo State, Brazil     

Anna Tengberg  Michael Stocking  & Sonia Carmela Falci Dechen 《Geografiska Annaler: Series A, Physical Geography》1997,79(1-2):95-107

Soil erosion is the principal threat to agricultural sustainability, affecting both the characteristics of the in situ soil and its productive potential. However, soils vary in their resilience and there are very few empirical data upon which to appreciate the degree and type of impact on the soil caused by erosion. This paper describes an experiment designed to generate such data based on soil loss and runoff plots, and it reports on nearly nine years of experience with the design at the Instituto Agronômico, Campinas, Brazil on a Latosol (Oxisol). After seven years of erosion induced by four levels of artificial cover, the effective rainfall on the most eroded soil was 20 percent less than on the control full cover. Crop yields were also found to be significantly affected: in 1995 by nearly 700 kg/ha and in 1996 by over 1000 kg/ha—a 50% decline in yield, amounting to a loss of 4 kg/ha of maize per tonne of cumulative soil loss. Losses of nutrients (organic C, P, K, Ca and Mg) in the runoff and eroded soil were also significant with far higher levels of loss associated with the eroded sediment. Changes in the in situ soil were less clear, but a test of trends showed that the decreases in organic matter and increases in acidity could unambiguously be attributed to soil erosion. Average enrichment ratios of the eroded sediment were 1.3 for organic C, 2.6 for P, 0.7 for K, 1.3 for Ca and 1.2 for Mg. Erosion has also affected the maize quality—mainly N, Ca and B nutrient content. Through these various measures, we conclude that seven years of induced erosion has had a marked effect on soil productivity, and for the first time we are now in a position to begin calculating the financial impact of the erosion process on future yields and farmer livelihoods.  相似文献   

On the origin of some mica-lamprophyres: experimental evidence from a mafic minette   总被引：7，自引：3，他引：7  

Sonia Esperança  John R. Holloway 《Contributions to Mineralogy and Petrology》1987,95(2):207-216

Experimental melting relationships for a mafic minette (mica-lamprophyre) from Buell Park, Arizona were determined under fO₂ conditions equivalent to the ironwüstite-graphite and quartz-fayalite-magnetite buffers, at pressures of 10–20 kbar. A comparison between experimental products and phenocrysts in the most primitive minettes indicates that those lavas preserve a near-liquidus assemblage of olivine, diopside and Ti-rich phlogopite crystallized in the upper mantle under fO₂QFM and in the presence of an H₂O-bearing fluid phase. It is suggested that micalamprophyric (minette) magmas may originate from a metasomatized, garnet-bearing peridotitic source at deeper levels in the mantle (P20 kbar) but can also be in equilibrium with a phlogopite-bearing wehrlite (±opx) source at pressures of 17–20 kbar, under reducing or oxidizing mantle conditions. Owing to their rapid crystallization rate and high liquidus temperatures, a series of potassic daughter melts (potassic latites and felsic minettes) can be formed by segregation from mafic minette parents during their ascent through the cooler continental crust. The preservation of olivine in equilibrium with phlogopite phenocrysts in primitive minettes precludes a petrogenetic process dominated by assimilation/fractional crystallization in a shallow magma chamber and supports a model by which some lamprophyric magmas are brought to near surface conditions at temperatures in the range of 1,000–1,200° C and chilled rapidly.  相似文献   

Volcaniclastic resedimentation on the northern slope of Vesuvius as a direct response to eruptive activity     

Annamaria Perrotta  Claudio Scarpati  Giuseppe Luongo 《Landslides》2006,3(4):295-301

A new archaeological excavation on the northern slope of Vesuvius has provided invaluable information on the eruptive activity and post-eruptive resedimentation events between the late Roman Empire and 1631. A huge Roman villa, thought to belong to the Emperor Augustus, survived the effects of the 79 a.d. Plinian eruption, but was mainly engulfed in volcaniclastic materials eroded and redeposited immediately after a subsequent eruption or during repose periods. Primary pyroclastic deposits of the 472 a.d. eruption are only few centimeters thick but are overlain by reworked volcaniclastic deposits up to 5 m thick. The resedimented volcaniclastic succession shows distinct sedimentary facies that are interpreted as debris flow deposits, hyperconcentrated flow deposits, and channel-fill deposits. This paper has determined that the aggradation above the roman level is about 9 m in 1,200 years, leading an impressive average rate of 0.75 cm/year.  相似文献