The western and northern margin off svalbard     

Eirik Sundvor  Olav Eldholm   《Tectonophysics》1979,59(1-4)

Recent geophysical measurements, including multi-channel seismic reflection, on the Svalbard passive margin have revealed that it has undergone a complex geological history which largely reflects the plate tectonic evolution of the Greenland Sea and the Arctic Ocean. The western margin (75–80°N) is of a sheared-rifted type, along which the rifted margin developed subsequent to a change in the pole of plate rotation about 36 m.y. B.P. The north-trending Hornsund Fault on the central shelf and the eastern escarpment of the Knipovich Ridge naturally divide the margin into three structural units. These main marginal structures strike north, paralleling the regional onshore fault trends. This trend also parallels the direction of Early Tertiary plate motion between Svalbard and Greenland. Thus, the western Svalbard margin was initially a zone of shear, and the shear movements have affected the adjacent continental crust. Although, the nature and location of the continent—ocean crustal transition is somewhat uncertain, it is unlikely to lie east of the Hornsund Fault. The northern margin, including the Yermak marginal plateau, is terminated to the west by the Spitsbergen Fracture Zone system. This margin is of a rifted type and the preliminary analysis indicates that the main part of the investigated area is underlain by continental crust.  相似文献   

Research in Polar and Alpine Geomorphology: (B. D. Fahey and R. D. Thompson,Eds.). Geoabstracts Ltd., Norwich,England, pp. 206. 1973     

Olav Slaymaker 《Quaternary Research》1975,5(2):305-306

  相似文献   

Compaction bands and induced permeability reduction in Tuffeau de Maastricht calcarenite     

Theocharis Baxevanis  Euripides Papamichos  Olav Flornes  Idar Larsen 《Acta Geotechnica》2006,1(2):123-135

The mechanical behavior and permeability of the Tuffeau de Maastricht calcarenite were studied. Compactions bands were found to form in the “transitional” regime between brittle faulting and cataclastic flow. In order to predict the formation of compaction bands, bifurcation analysis was applied on a model developed by Lade and Kim. The numerical results proved to be in good agreement with the experimental ones where the localization point was identified to be the onset of shear-enhanced compaction (a threshold in differential stress after which significant reduction of porosity is induced). Before the onset of shear-enhanced compaction, permeability was primarily controlled by the effective mean stress, independent of the deviatoric stresses. With the onset of shear-enhanced compaction, however, coupling of the deviatoric and hydrostatic stresses induced considerable permeability and porosity reduction.  相似文献   

Determination of Postglacial Land Uplift in Fennoscandia from Leveling, Tide-gauges and Continuous GPS Stations using Least Squares Collocation     

Olav Vestøl 《Journal of Geodesy》2006,80(5):248-258

Precise leveling, tide-gauge recordings and time series from continuous GPS stations are all sources of information about the ongoing postglacial land uplift in Fennoscandia. This article describes how to gather these three sources of data together in a least-squares collocation adjustment in order to calculate uplift rates, as well as new heights for the benchmarks in the leveling network. The estimated reliability of the resulting uplift model is in general better than 0.4 mm/year, decreasing in areas of fewer data.A smoother and extended version of the land uplift model described here is used in the adjustment of the new height system in Sweden (RH 2000) under the name RH 2000 LU. Later on, the name was changed to NKG2005LU. The Finnish Geodetic Institute (FGI) has decided to use the same model when they calculate their new height system, N2000.  相似文献   

Linearized elastic parameter sections1     

Bjrn Ursin  Bjrn Olav Ekren  Egil Tjland 《Geophysical Prospecting》1996,44(3):427-455

Contrasts in elastic parameters can be estimated directly from seismic data using offset-dependent information in the PP reflection coefficient. A linear approximation to the PP reflection coefficient including three coefficients is fitted to the data, and relative contrasts in various elastic parameters are obtained from linear combinations of the estimated coefficients. Linearized elastic parameter sections for the contrasts in P-wave impedance, P-wave velocity, density, plane-wave modulus, and the change in bulk modulus and shear modulus normalized with the plane-wave modulus are estimated. If the average P- to S-wave velocity ratio is known, linearized parameter sections including the contrast in the average P- to S-wave velocity ratio and a fluid factor section can be computed. Applied to synthetic data, visual comparison of the estimated and true elastic parameter sections agree qualitatively, and the results are confirmed by an analysis of the standard deviation of the estimated parameters. The parameter sections obtained by inversion of a shallow seismic anomaly in the Barents Sea are promising, but the reliability is uncertain because neither well data nor regional trends are available.  相似文献   

Editorial. Geomorphological sociology     

Michael Church  Basil Gomez  Edward J. Hickin  Olav Slaymaker 《地球表面变化过程与地形》1985,10(6):539-540

  相似文献   

The influence of molecular blends and non-thermal line broadening on the profile of the Zeeman triplet λ5250.22 in sunspots     

Olav Kjeldseth Moe 《Solar physics》1973,33(2):393-401

Calculations of the umbral profile of the Zeeman triplet 5250.22 are presented. We have taken into account the effect of a molecular blend from TiO at 5250.24 causing an apparent -component even for longitudinal magnetic fields. Also included is the depression of the spot continuum due to line wings and veiled weak lines in the umbra spectrum. The effect of different amounts of non-thermal broadening is investigated.The results point to the need of a better theoretical treatment of molecular and atomic blends and to the importance of more reliable values for the non-thermal broadening in sunspots. Furthermore, the importance of a proper stray light correction is noted, particularly including the stray light from the penumbra.  相似文献   

Evaluation of the frequency of skipped spawning in Norwegian spring-spawning herring     

James Kennedy  Jon Egil Skjraasen  Richard D.M. Nash  Aril Slotte  Audrey J. Geffen  Olav S. Kjesbu 《Journal of Sea Research》2011,65(3):327-332

Based upon an under-representation of second time spawners on the spawning grounds between 1935 and 1973, researchers have suggested that Norwegian spring-spawning (NSS) herring (Clupea harengus) frequently skip their second spawning event. In order to evaluate this claim with direct evidence, herring were collected over a period of three years from statutory surveys and commercial catches over a wide area covering the feeding, over-wintering and spawning grounds. The development stage of the ovaries was assessed and the intensity of atresia quantified. Only a negligible number of the analysed herring caught were considered likely to skip spawning, thus this phenomenon does not appear to be a common feature of the NSS herring stock at present. In addition, considering the reproductive strategy of herring, it seems doubtful that skipping the second spawning event has ever frequently occurred in this stock.  相似文献   

Pupils' knowledge and awareness of geography when starting upper secondary school in Norway     

Olav Fjær 《Norsk geografisk tidsskrift. Norwegian journal of geography》2013,67(3):135-141

The author, an upper secondary teacher in geography, has conducted various surveys and questionnaires among pupils every year, for 30 years. The article examines his pupils' knowledge of geography when they start upper secondary school. During their first lesson in geography they are presented with a questionnaire designed to test their knowledge of concepts, places, and causal relationships. In addition, they are asked about their perceptions of geography and expectations when they start to study a new subject. The author finds it valuable and important as a teacher to know what his pupils have learned during their lower secondary education because such information could be used to adapt upper secondary education in geography to the pupils' abilities. Further, it is important to motivate, create expectations, and develop awareness of geography. In addition to discussing pupils' knowledge of geography, the article shows briefly how school curricula and geography teaching have changed in Norwegian lower secondary schools since the early 1970s.  相似文献   

Effects of trawl sampling variability on precision of acoustic abundance estimates of gadoids from the Barents Sea and the Gulf of Alaska   总被引：3，自引：2，他引：1  

Godo  Olav Rune; Karp  William A.; Totland  Atle 《ICES Journal of Marine Science》1998,55(1):86-94

  相似文献