Preface     

Jean-Claude Flageollet  Mario Panizza  Mauro Soldati 《Geomorphology》1996,15(3-4)

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Ground temperature history in central Europe from borehole temperature data     

Christoph Clauser  Jean-Claude Mareschal 《Geophysical Journal International》1995,121(3):805-817

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Structure of melt flow channels in the mantle   总被引：1，自引：0，他引：1  

G. N. Savelieva  A. V. Sobolev  V. G. Batanova  P. V. Suslov  G. Brügmann 《Geotectonics》2008,42(6):430-447

Structural events during the formation of the mantle peridotite section in the Voikar-Syn’ya massif of the Polar Urals are considered. The structural units of the mantle section were formed during several deformation stages. Dunite bodies in restitic peridotites were formed in the course of deformation that completed the formation of large-scale folds of high-temperature plastic flow of mantle material. The final stage of deformation accompanied by migration of melt through harzburgite occurred in the shallow mantle in the setting of suprasubduction spreading related to the ascent of a mantle diapir. The rate of plastic deformation was relatively low. As a result, the intracrystal translation gliding of dislocations in olivine was the main mechanism in both harzburgite and dunite. The paths of focused melt flow are marked by dunite veins and associated pyroxenite and chromitite. It is suggested that stress concentration in fold hinges and their abrupt relaxation with formation of orthogonal network of weakened zones with high permeability was one of the possible mechanisms of the formation of melt conduits. The dispersed melt ascending from a great depth spontaneously migrated toward these zones. The distribution and structure of chromitite bodies reflect multistage formation of dunite, nonstationary dynamics of melt flow through restite, and abrupt variations of local stress fields in the areas adjacent to melt conduits.  相似文献   

Weather and traffic accidents in the Czech Republic, 1979–2020     

Brázdil  Rudolf  Chromá  Kateřina  Zahradníček  Pavel  Dobrovolný  Petr  Dolák  Lukáš 《Theoretical and Applied Climatology》2022,149(1-2):153-167

Theoretical and Applied Climatology - Police records, kept in the form of yearbooks, enabled analysis of the possible relationships between traffic accidents and the weather in the Czech Republic...  相似文献   

Maximum sedimentation ages and provenance of metasedimentary rocks from Tinos Island,Cycladic blueschist belt,Greece     

Tim Hinsken  Michael Bröcker  Jasper Berndt  Claudia Gärtner 《International Journal of Earth Sciences》2016,105(7):1923-1940

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Weibull Wind-Speed Distribution Parameters Derived from a Combination of Wind-Lidar and Tall-Mast Measurements Over Land,Coastal and Marine Sites     

Sven-Erik Gryning  Rogier Floors  Alfredo Peña  Ekaterina Batchvarova  Burghard Brümmer 《Boundary-Layer Meteorology》2016,159(2):329-348

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On a model of frictional sliding     

Y. Estrin  Y. Bréchet 《Pure and Applied Geophysics》1996,147(4):745-762

A model of frictional sliding with anN-shaped curve for the sliding velocity dependence of the coefficient of friction is considered. This type of friction law is shown to be related to dynamic i.e., velocity dependent ageing of asperity junctions. Mechanisms of ageing for ductile (Bowden-Tabor) and brittle (Byerlee) materials, though different in nature, lead to qualitatively similarN-shaped velocity dependencies of the coefficient of friction. Estimates for the velocities limiting the range of negative velocity sensitivity of the coefficient of friction are obtained for the ductile case and—albeit with a lesser degree of reliability—for the brittle one. It is shown by linear stability analysis that discontinuous sliding (stick-slip) is associated with thedescending portion of theN-shaped curve. An instability criterion is obtained. An expression for the period of the attendant relaxation oscillations of the sliding velocity is given in terms of the calculated velocity dependence of the coefficient of friction. It is suggested that the micromechanically motivated friction law proposed should be used in models of earthquakes due to discontinuous frictional sliding on a crustal fault.  相似文献   

A Possible Photochemical Link Between Stratospheric and Near-Surface Ozone on Swiss Mountain Sites in Late Winter   总被引：2，自引：0，他引：2  

Stefan Brönnimann  Urs Neu 《Journal of Atmospheric Chemistry》1998,31(3):299-319

Record high near-surface ozone concentrations at two elevated sites (Chaumont, 1140 m asl, and Rigi, 1030 m asl) in Switzerland were observed simultaneously with extremely low total ozone during a fair weather period in mid-February 1993. An analysis of ozone, temperature, humidity, and wind profiles suggests that the surface ozone peaks were most possibly generated within the region in a layer between about 1000 and 1500 m asl. Mean diurnal cycles of ozone concentration during the period shows a strong increase from late morning to late afternoon at Chaumont and at the same time a decrease at the high alpine site Jungfraujoch (3580 m asl). The different diurnal ozone cycles can both be explained photochemically by taking into account the large difference in NOx concentrations (about two orders of magnitude) between the sites. Photochemical processes are also indicated by the diurnal cycles of NO2 and NO concentration. As a strong photochemical activity is not expected in mid-February at 47°N, we hypothesize that the extremely low total ozone played a role. Total ozone controls the amount of UV-B radiation reaching the troposphere and thus influences photochemical processes. Using a radiation model, we calculated an increase in ozone photolysis at Chaumont and Jungfraujoch of 73% and 83%, respectively, on the day with the lowest total ozone (243 DU) compared to average February conditions (335 DU). It is suggested that total ozone changes have the potential to stimulate photochemistry sufficiently to produce the observed surface ozone peaks at Chaumont and Rigi of 61 and 64 ppbv, respectively. A fog layer just below Chaumont during these days probably also influenced photochemistry, but on a smaller spatial scale. Our empirical results on the influence of changing UV radiation on tropospheric photochemistry are in close agreement with model studies of other groups. Although this case study represents unique conditions, a distinct anticorrelation between near-surface ozone at Chaumont and total ozone also appears in other years (1992–1997) when selecting fair weather days in mid-February. However, other influences cannot be excluded. The selected days provide evidence of a significant photochemical source of ozone in the mid-latitude lower troposphere in late winter.  相似文献   

Impacts « multi-échelle » d'un échange (Mg,Ca)–Pb et ses conséquences sur l'augmentation de la perméabilité d'une bentonite     

Nevila Jozja  Patrick Baillif  Jean-Claude Touray  Charles-Henri Pons  Fabrice Muller  Carole Burgevin 《Comptes Rendus Geoscience》2003,335(9):729-736

The article addresses the structural effects of solutions of lead nitrate on a suspended or compacted bentonite. A permeability increase is observed on compacted clay. Investigating the composition of output solution, using X-Rays Diffusion at Small Angles and Scanning Electron Microscopy, this permeability increase is explained from structural variations at nanometric (reduction of particle size) and micrometric scales (microfissuration of aggregates). To cite this article: N. Jozja et al., C. R. Geoscience 335 (2003).  相似文献   

Present state of the Baltic Coastal Waters off Mecklenburg-Vorpormmern,Germany     

Dr. L. Brügmann  A. Bachor 《GeoJournal》1990,22(2):185-194

The coastal waters of the former GDR comprising more than 9000 sqkm with a maximum width of 12 n.m. from the baseline and the 1600 sqkm inner bodden waters with a volume of about 6 cu.km are of unique importance to trade by providing transport by sea including three ferry links, to fishing, recreaation and other uses. Based on the results of monitoring programmes carried out between 1973 and 1988 and reviewing existing literature, the state of these waters is discussed. The paper starts with a characterization of the environmental background conditions of the area including its catchment region. Data on population density, fishing, industry, agriculutre and other information is tabulated as deemed necessary to understand the sensitivity of the coastal water and potential impacts on their state.The contamination load released into bodden waters and further into the Baltic Sea by eight relatively small rivers is quantified. In relation to the concentrations of contaminants such as heavy metals, petroleum hydrocarbons and organochlorines, there are no severe environmental problems. However, nutrients and their cycling in the system cause eutrophication. This results (a) in reduced usefulness of the bodden waters for recreation and even fishing, (b) in anoxic sediments and (c) in declining benthos colonization. For some of the contaminants inter-annual and spatial trends were found to be of statistical significance. Summarizing the present knowledge on the state of the coastal waters and realising obvious gaps in the complex scientific understanding and forecasting, measures required to reduce the contaminant load are proposed.  相似文献