Hydrogeologic studies for nuclear-waste disposal in Sweden

Safety Report 1997 (SR 97) of the Swedish Nuclear Fuel and Waste Management Company is a comprehensive performance assessment of three hypothetical radioactive waste repositories in Sweden. It includes hydrogeologic studies (data compilation, parameter synthesis, and groundwater flow modeling) to determine groundwater flow and the associated uncertainties for the three sites. This report reviews and compares the hydrogeologic characterization programs, the site characteristics, and the groundwater flow models used in the SR 97 performance assessment. Although differences in site-characterization programs tend to mask differences in site characteristics, the sites do have notable differences that affect the results of the performance assessment. The effects of model uncertainties evaluated by the variant cases appear to be smaller than the variability of results for the base case (best estimate of site conditions) of each site. Electronic Publication     

Calibration of regional pollen data to construct maps of former forest types in southern Sweden

A method was developed to construct maps of former forest types based on regional pollen data in southern Sweden. The considered species were Alnus, Betula, Carpinus, Corylus, Fagus, Fraxinus, Juniperus, Picea, Pinus, Populus, Quercus, Salix, Tilia and Ulmus. A network of 37 regional pollen sites with high data quality from lakes and peat deposits were selected from Sweden south of 60 ° N. Pollen percentage values were calculated and converted into estimates of tree composition. For controlling the reliability of the reconstruction, the estimates from the core-tops were compared with present day forest inventory data, and local pollen diagrams were compared with the regional pollen diagrams. An inverse distance weighted interpolation algorithm was used to generate maps for each tree species distribution at 2000 BP, 1500 BP, 1000 BP, 500 BP and 0 BP. A supervised classification routine was implemented to generate nine different forest types common to the five studied time intervals. The maps show that the amounts and patterns of distribution of the species and the forest types have varied in a significant but systematic manner through time. The changes are due to human activities, migrational patterns and changes in climate. These maps will be of value as a basis for future landscape planning, forestry and conservation of biodiversity.This is the 20th in a series of papers published in this special AMQUA issue. These papers were presented at the 1994 meeting of the American Quaternary Association held 19–22 June, 1994, at the University of Minnesota, Minneapolis, Minnesota, USA. Dr Linda C. K. Shane served as guest editor for these papers.     

The blast near Eschenlohe,Bavaria, recorded at Průhonice

Резюме Приводятся результаты анализа записей двух камерных взрывов, имевших место 15-го Февраля 1958 г. в Баварии. Взрывы были регистрированы двумя вертикальными электродинамическими сейсмографами, иаготовленными в Геофизическом институте ЧСАН и назначенными для регистравии слабых тектонических толчков.

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Address: Boční II, Praha 13-Spořilov.     

Some physical and chemical properties of lakes in north-eastern Norway

Summary Chemical and physical properties in 12 lakes in the north-easternmost part of Norway are studied. Geologically the lakes are situated on the pre-cambrian “Baltic shield”, with metamorphic and intrusive rocks that are not easily soluble. Vertical series of temperature, pH, O₂ and x₁₈ together with colour measurements and transparency indicate that the lakes are temperate and fundamentally oligotrophic, some with a dystrophic character. Some individual differences are discussed, with special reference to the surroundings, flow-through rate and morphometry. In accordance with the geology of the area the amount of electrolytes is small. Major ions (Ca, Mg, Na, K, HCO₃, SO₄ and Cl) are analysed. The greatest differences in the composition of these ions in the lakes are shown to be due mainly to the varying proximity to the sea and to geological differences. Rain is shown to be the most important factor in supplying major ions toat least some of the lakes. Individual variations are discussed, and comparisons are made with the ionic composition of water in other districts.

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Zusammenfassung An 12 im n?rdlichesten Teil von Norwegen, auf dem pr?kambrischen Baltischen Schild gelegenen Seen werden die chemischen und physikalischen Eigenschaften studiert. Das Einzugsgebiet besteht aus schwerl?slichem, metamorphem und intrusivem Gestein. Die vertikale Verteilung von Temperatur, pH, O₂ und x₁₈ samt Farbmessungen und Transparenz zeigt, dass die Seen dem temperierten Typus angeh?ren und im wesentlichen oligotroph sind, einige von dystrophem Charakter. Einige individuelle Unterschiede werden er?rtert mit besonderer Berücksichtigung der Umgebung, der Durchflutungszeit und der Morphometrie. In übereinstimmung mit der geologischen Beschaffenheit der Umgebung ist der Elektrolytgehalt neigdrig. Die dominierenden Ionen (Ca, Mg, Na, K, HCO₃, SO₄ und Cl) werden analysiert. Es wird nachgewiesen, dass die gr?ssten Unterschiede in der Zusammensetzung dieser Ionen in den Seen auf die verschiedene Entfernung vom Meer und auf geologische Unterschiede zurückzuführen sind. Für einige der Seen wird nachgewiesen, dass der Regen als wichtigster Faktor für ihre Versorgung mit Ionen anzusehen ist. Es werden individuelle Unterschiede er?rtert und Vergleiche mit der ionalen Zusammensetzung von Gew?ssern anderer Gegenden gezogen.

     

Core waves recorded in central Europe

Summary The core waves recorded at four seismograph stations in Central Europe were investigated with the aim to find the most suitable set of travel-time curves and a fitting model of the core structure. Another travel-time curve was constructed by means of time differences between the core phases. The differences in the features of the travel-time curves were studied using records of shallow, intermediate and deep shocks from the same focal region (Tonga).