Redefining active volcanoes: a discussion   总被引：2，自引：0，他引：2  

Alexandru Szakács 《Bulletin of Volcanology》1994,56(5):321-325

The analysis of the current definitions of active volcanoes indicates that they are empirical, conventional, inaccurate, nongeological, and arbitrarily constraining. Redefinition is therefore needed. One possible approach is to refine the current empirical definitions. A statistically reasonable and practical redefinition using a geologically based time convention-Holocene or 10000 years-is suggested. A set of time conditions according to volcano typology-i.e. 1000; 10000 and 100000 years for high-frequency basaltic shields, andesitic-dacitic composite volcanoes and low-frequency large silicic calderas, respectively-as further refinement of the empirical definition is also envisaged. Devising a phenomenological definition as a theoretical approach is another possibility, but in practice extant diagnostic means are still unsatisfactory to discriminate accurately between dormant and extinct volcanoes. As a consequence of the redefinition, a classification of volcanoes according to their eruptive status is proposed. Redefinition of active volcanoes might increase accuracy in the usage of basic terms in volcanology and influence volcanic hazard assessment and risk mitigation projects.  相似文献   

The Dynamics of Small Postglacial Lake Basins and the Nature of Their Archaeological Record: A Case Study of the Middle Palaeolithic Site Neumark‐Nord 2, Germany     

Eduard Pop  Corrie Bakels  Wim Kuijper  Herman Mücher  Madeleine van Dijk 《Geoarchaeology》2015,30(5):393-413

Due to favorable conditions of preservation, sedimentary basins provide rich records of human behavior and its environmental context. The conditions for the preservation of archaeological material however vary between basin types (large, river‐fed or small, closed basins), while conditions also differ within a particular basin environment. The goal of this paper is to understand how the dynamics of a small postglacial basin such as Neumark‐Nord 2, a context that dominates the Eemian archaeological record, affected the archaeology situated at its basin margin. The approach used here is to correlate the archaeological record with reconstructions of patterns of deposition and the water conditions within the basin, using lithology, micromorphology, pollen, and macroremains from a transect running from the basin center to the margin. The results show that (1) find levels were exposed to overland flow‐induced winnowing, which vertically concentrated finds but did not cause significant transport, (2) find levels correspond to phases of increased water presence in the basin, and (3) lateral shifts in hominin activity areas may reflect adjustments in the water level. The research shows the importance of large‐scale archaeological excavations and a multidisciplinary sampling strategy that covers both the basin center and the margins, when studying postglacial basin localities like Neumark‐Nord 2.  相似文献   

CMSAF products Cloud Fraction Coverage and Cloud Type used for solar global irradiance estimation     

Viorel Badescu  Alexandru Dumitrescu 《Meteorology and Atmospheric Physics》2016,128(4):525-535

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Comments on the article "Erosion calderas: origins, processes, structural and climatic control" by Karátson D., Thouret J.-C., Moriya I., Lomoschitz A. (1999) Bull Volcanol 61:174-193     

Alexandru Szakács  Michael Ort 《Bulletin of Volcanology》2001,63(4):289-290

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Environmental protection in the Apuseni Mountains: The role of Environmental Non-Governmental Organisations (ENGOs)     

Mircea Buza  Levente Dimen  Grigor Pop  David Turnock 《GeoJournal》2001,55(2-4):631-653

The Apuseni Mountains constitute one of the most interesting parts of the Carpathians in terms of landscape, biodiversity and culture. Yet dislocations are now severe and there are development threats which also require a significant response. On the one hand there are some severe pollution problems associated with mining areas developed in the communist period which require remedial action and the cases of Roşia Montana and Zlatna are discussed. On the other hand, there are forest and pasture zones – especially the Padiş Plateau – which are coming under heavy pressure from farmers seeking to enhance their incomes following the decline of mining and manufacturing which has left many households without salaries. At the same time, tourist pressure is growing. Actions are already being taken to limit pollution damage and develop sustainable landuse practices. There is a national park project linked with nature reserves comprising picturesque landscapes, a rare flora and fauna and distinct geological and palaeotological formations (including fossil ice). There are major tourist attractions and with proper management they could become part of a development programme of the countryside. However it is essential that all stakeholders adopt sustainable practices and this means that official programmes – including the future national park authority administration's work in environment protection and tourism management – are backed up by Environmental Non-Governmental Organisations (ENGOs). The paper reviews their diverse activities and concludes that they are making a very substantial contribution in ensuring that the potentials of isolated regions can be utilised in a manner consistent with nature conservation. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Interplay of tectonics and neogene post-collisional magmatism in the intracarpathian region   总被引：6，自引：0，他引：6  

Ioan Seghedi  Ion Balintoni  Alexandru Szakcs 《Lithos》1998,45(1-4):483-497

Distribution of the Neogene calc-alkaline magmatism of the Carpathian arc is directly related in space and time to the kinematics of the two major terranes of the Intracarpathian area (Alcapa, Tisia-Getia) along the south-eastern border of the European plate. In the West Carpathians and adjacent areas, the volcanic activity occurred between 20–11 Ma, with large volumes of both acidic and intermediate rocks, generally distributed randomly, sometimes transversally to the orogenic belt and as rare small occurrences along the Flysch belt. In the East Carpathians, the volcanic rocks are distributed along the northern margin of the Zemplin block, the north–easternmost part of the Alcapa and eastward along the front of the Getic block, at the contact with European plate. Between Tokaj-Slanské-Vihorlat up to northern Cãlimani Mountains, the magmatism occurred between 14–9 Ma, and along the Cãlimani-Harghita chain between 9–0.2 Ma. The calc-alkaline magmatic rocks of the Apuseni Mountains are located in the interior of the Tisia block and occurred between 14–9 Ma. The generation of the calc-alkaline magmatism is considered here as the result of complex interplay between plate roll-back and lithospheric detachment tectonic processes and the break-off of the subducted plate, mostly in a post-collisional setting. (1) The magmatites of the Western Carpathians and the Pannonian basin were generated in direct relation to subduction roll-back processes, over the downgoing slab, during the period of lateral extrusion and back-arc extension. In this area, characterized by maximum crustal shortening, we can infer further delamination processes to explain the generation of magmas. (2) The magmatic rocks from the northern sector of the East Carpathians (Tokaj-Slanské-Vihorlat up to the Northern Cãlimani Mountains), resulted after subduction roll-back processes and an almost simultaneous break-off of the descending plate all along the arc segment during main clockwise rotation of the Intracarpathian terranes. (3) In the eastern sector of the East Carpathians (Cãlimani up to Harghita Mountains), the magmatic rocks were generated through partial melting of the subducted slab followed by gradual break-off of the subducted plate along strike (north to south). (4) The Apuseni Mts. magmatic activity resulted in transtensional tectonic regime by decompressional melting of lithospheric mantle, during the translation and rotation of Tisia-Getia block.  相似文献   

Deep seismic soundings in Romania     

Ion Cornea  Florin Rădulescu  Alexandru Pompilian  Adrian Sova 《Pure and Applied Geophysics》1981,119(6):1144-1156

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Impact of the past mining activity in Roşia Montană (Romania) on soil and vegetation     

Adina-Laura Lazăr  Călin Baciu  Carmen Roba  Tiberius Dicu  Cristian Pop  Călin Rogozan  Cristina Dobrotă 《Environmental Earth Sciences》2014,72(11):4653-4666

The paper presents the results of a combined soil and vegetation survey in Ro?ia Montan? mining area (western Romania), famous for its gold and silver deposits, extensively exploited over the last 2,000 years. As the ore extraction has ceased in 2006 and new operations could be initiated in the future, the study contributes to the definition of the environmental baseline. Samples of topsoil and leaves of the tree species Betula pendula and Carpinus betulus have been collected from the inside and outside of the mining area, on a total surface of more than 60 km². The pH and heavy metal concentrations (Cd, Cr, Cu, Ni, Pb, and Zn) have been measured on 262 soils/sediments samples, revealing the predominantly acidic character of soils and the generally low contents of heavy metals. Stronger acidity and higher contents of heavy metals have been noticed in the proximity of the mining site, on the tailings and waste rock dumps, and along the streams with acid water. More than 100 leaf samples have been analysed for the same heavy metals as soils and also for chlorophyll fluorescence and pigment concentrations. B. pendula has shown a particular ability to concentrate Zn in leaves, at levels that may greatly exceed the Zn content in the corresponding soil samples. The correlation between the heavy metal contents in leaves and in soils, in most of the cases, is not very strong, presumably in relation to the low concentrations in soils. The chlorophyll concentration in leaves of B. pendula slightly diminishes on soils with low pH.  相似文献   

Changes in annual temperature extremes in the Carpathians since AD 1961   总被引：1，自引：1，他引：0  

Marius-Victor Birsan  Alexandru Dumitrescu  Dana Magdalena Micu  Sorin Cheval 《Natural Hazards》2014,74(3):1899-1910

The Carpathian Mountains region cover areas from seven countries of central and southeastern Europe, the mountain chain having major regional influences on the temperate climate, specific to latitudes between 43°N and 49°N. In order to identify changes in the annual temperature extremes, the Mann–Kendall nonparametric trend test has been applied to several thermal indices, recommended by the expert team on climate change detection and indices. The indices were computed from gridded daily datasets of minimum and maximum temperature at 0.1° resolution (~10 km), available online within the framework of the project CarpatClim (climate of the Carpathian region) for the period 1961–2010. The results show decreasing trends in cold-related indices, especially in the number of frost days, and increasing trends in warm-related ones. The trend patterns are consistent over the region, i.e., there are no mixed trends for a given index. Regional differences in climate extreme trends within the Carpathian region are related to altitude, rather than latitude. The number of summer days is increasing over the entire area, while the number of tropical nights presents upward trends mainly at lower elevations. The Warm Spell Duration Index presents upward trends over 60 % of the region. The (annual) East Atlantic pattern shows strong correlations with the warm-related indices. Our results are in agreement with previous temperature-related studies in the region.  相似文献   

Statistical-dynamical downscaling of wind roses over the Czech Republic     

Jaroslav Svoboda  Zuzana Chladova  Lukas Pop  Jiri Hosek 《Theoretical and Applied Climatology》2013,112(3-4):713-722

The present study describes a new method for statistical-dynamical downscaling that combines two different approaches, namely, a set of patterns simulated with a numerical flow model and a transformation function used to process both calculated data and measurements at a reference station. The combined method produces wind roses and wind speed histograms at an arbitrary location in the model domain. The inflow wind direction represented the key parameter to define a set of wind field simulations. The other two inflow parameters, namely, thermal stratification and geostrophic wind speed, were derived from corresponding averaged soundings. The results showed that in the Czech Republic, there are areas where wind roses are deformed by the surrounding terrain. The deformations occur in relatively shallow and wide valleys, and they are more sensitive to the inflow wind direction. Calculated wind roses are compared to corresponding observations at 22 synoptic stations. The most frequent wind direction sector in simulations agreed with measurements at 17 stations. The resulting error in frequency in that sector was under 5 % at 10 stations. In general, the main features of the wind roses are modelled well, even at a relatively large distance from the reference station. However, better performance was achieved for smaller distances between reference station and the site. In further studies, a more extensive set of flow patterns with reduced intervals of thermal stratification and wind speed will likely improve calculated wind roses.  相似文献