3D structure of the Earth's crust beneath the northern part of the Bohemian Massif   总被引：1，自引：1，他引：1  

Mariusz Majda&#x;ski  Elena Kozlovskaya  Marek Grad  SUDETES Working Group 《Tectonophysics》2007,437(1-4):17-36

The SUDETES 2003 wide-angle refraction/reflection experiment covered the area of the south-western Poland and the northern Bohemian Massif. The good quality data that were gathered combined with the data from previous experiments (POLONAISE'97, CELEBRATION 2000) allowed us to prepare a 3D seismic model of the crust and uppermost mantle for this area. We inverted travel times of both refracted and reflected P waves using the JIVE3D package. This allowed us to obtain a model of P-wave velocity distribution as well as the shape of major boundaries in the crust. We also present a detailed uncertainty analysis for both the boundary depths and the velocity field. In doing the uncertainty analysis we found an interesting, strong dependence between uncertainty and inversion scheme (order of used phases). We also compared the model with surface geology and found good correlation between velocity inhomogeneities in the uppermost crust (down to 2 km) and major geological units. The higher velocity lower crust (6.9–7.2 km/s) could result from remelting of the lower crust or magmatic underplating.  相似文献   

Diurnal atmospheric forcing and temporal variations of the nutation amplitudes     

C. Bizouard  A. Brzeziński  S. Petrov 《Journal of Geodesy》1998,72(10):561-577

A 29-year time-series of four-times-daily atmospheric effective angular momentum (EAM) estimates is used to study the atmospheric influence on nutation. The most important atmospheric contributions are found for the prograde annual (77 μas), retrograde annual (53 as), prograde semiannual (45 as), and for the constant offset of the pole (δψsinɛ₀=−86 as, δɛ=77 as). Among them only the prograde semiannual component is driven mostly by the wind term of the EAM function, while in all other cases the pressure term is dominant. These are nonnegligible quantities which should be taken into account in the new theory of nutation. Comparison with the VLBI corrections to the IAU 1980 nutation model taking into account the ocean tide contribution yields good agreement for the prograde annual and semiannual nutations. We also investigated time variability of the atmospheric contribution to the nutation amplitudes by performing the sliding-window least-squares analysis of both the atmospheric excitation and VLBI nutation data. Almost all detected variations of atmospheric origin can be attributed to the pressure term, the biggest being the in-phase annual prograde component (about 30 as) and the retrograde one (as much as 100200 as). These variations, if physical, limit the precision of classical modeling of nutation to the level of 0.1 mas. Comparison with the VLBI data shows significant correlation for the retrograde annual nutation after 1989, while for the prograde annual term there is a high correlation in shape but the size of the atmospherically driven variations is about three times less than deduced from the VLBI data. This discrepancy in size can be attributed either to inaccuracy of the theoretical transfer function or the frequency-dependent ocean response to the pressure variations. Our comparison also yields a considerably better agreement with the VLBI nutation data when using the EAM function without the IB correction for ocean response, which indicates that this correction is not adequate for nearly diurnal variations. Received: 10 September 1997 / Accepted: 5 March 1998  相似文献   

Tourist farms in Lower Silesia, Poland   总被引：1，自引：0，他引：1  

Stanisław Grykień 《GeoJournal》1998,46(3):279-281

In view of the small size of most Polish farms, attempts have been made to encourage diversification into rural tourism. The paper examines the progress made in Lower Silesia which has good resources for domestic and international tourism. Thanks to the promotional work of the Agricultural Consultative Centres over a hundred farms are now providing services. They do not generate a large share of the farm income but business is expanding and some areas are becoming very popular. Thus a base has been established for future expansion. Further development depends on easier access to credit and government support for ecological agriculture. Better promotion is also needed to increase interest in rural tourism in Poland and attract more visitors from abroad. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Mantle heat flow and geotherms for major tectonic units in central Europe     

Jacek Majorowicz 《Pure and Applied Geophysics》1978,117(1-2):109-123

The results of seismic measurements along the deep seismic sounding profile VII and terrestrial heat flow measurements used for construction of heat generation models for the crust in the Paleozoic Platform region, the Sudetic Mountains (Variscan Internides) and the European Precambrian Platform show considerable differences in mantle heat flow and temperatures. At the base of the crust variations from 440–510°C in the models of Precambrian Platform to 700–820°C for the Paleozoic Platform and the Variscan Internides (Sudets) are found. These differences are associated with considerable mantle heat flow variations.The calculated models show mantle heat flow of about 8.4–12.6 mW m^–2 for the Precambrian Platform and 31 mW m^–2 to 40.2 mW m^–2 for Paleozoic orogenic areas. The heat flow contribution originating from crustal radioactivity is almost the same for the different tectonic units (from 33.5 mW m^–2 to 37.6 mW m^–2). Considerable physical differences in the lower crust and upper mantle between the Precambrian Platform and the adjacent areas, produced by lateral temperature variations, could be expected. On the basis of carbon ratio data it can be concluded that the Carboniferous paleogeothermal gradient was much lower in the Precambrian Platform area than in the Paleozoic Platform region.  相似文献   

Electromagnetic induction study on dss profile No. V (carpathians)     

Jerzy Jankowski  Antoni Szymański  Jana Pěčová  Oldřich Praus  Václav Petr  Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1975,19(1):95-102

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Improvement of the geoid in local areas by satellite-to-satellite tracking     

Jan Kryński 《Journal of Geodesy》1979,53(1):19-36

Summary The concept of satellite-to-satellite tracking measuring the relative velocity of two orbiting satellites spaced some hundreds kilometers on a close orbit, provides now possibilities for the investigation of the Earth’s gravity field. In the paper only medium and short wave length effects affecting the measured relative velocity have been considered. Collocation is used in such an analysis of local geoid improvement, because this method allows to combine heterogeneous data in a consistent way. Covariance functions relevant for the particular case of a circular equatorial orbit are given. Two kinds of observation equations have been formulated. The choice of observation equation with regard to satellites configuration is discussed. It is found that it is sufficient to have a limited number of satellite-to-satellite observations in a 7^o×7^o area around the estimation point with distances between profiles of about 1^o.5 and between the two satellites forming the pair of 200+350 km; the altitude of satellite-to-satellite observations should be as low as possible. The accuracy of the geoid determination strongly depends on the degree and order of the reference field used. An accuracy of about ±1 m can be achieved with an assumed reference field of (40,40). The influence of measuring errors is discussed and it is shown that only satellite-to-satellite observations with accuracy better then 0.1 mm/sec will give an improvement of the geoid. Finally, some results on the combination of low-low satellite-to-satellite tracking and terrestrial gravity data are given. The proposed method seems to be especially interesting for unsurveyed areas. Furthermore, it has the practical advantage that only a local coverage data is needed.  相似文献   

5-alkylsalicylaldoximes as collectors in flotation of sphalerite,smithsonite and dolomite in a Hallimond tube     

Tadeusz Kiersznicki  Jacek Majewski  Jan Mzyk 《International Journal of Mineral Processing》1981,7(4):311-318

Flotation tests for sphalerite, smithsonite and dolomite were carried out in a Hallimond tube at various pH values and two concentrations of collector.Adsorption of 5-alkylsalicylaldoximes on the surface of minerals was examined and isotherms for 5-butylsalicylaldoxime plotted.It was shown that sorption intensity of 5-alkylsalicylaldoximes on the surface of minerals decreased in the order: smithsonite, sphalerite and dolomite.Relationship between length of aliphatic chain and collecting activity of 5-alkylsalicylaldoximes was investigated in microflotation tests in a Hallimond tube.5-Propylsalicylaldoxime proved to have the best selectivity in flotation for the range of parameters studied, taking the difference in flotation rates of smithsonite and dolomite as a criterion.It was found that modifications of pH value resulted in changes in both adsorption and flotation.  相似文献   

Improvement of the geoid in local areas by satellite gradiometry     

K. P. Schwarz  J. Kryński 《Journal of Geodesy》1977,51(3):163-176

Summary Satellite gradiometry is studied as a means to improve the geoid in local areas from a limited data coverage. Least-squares collocation is used for this purpose because it allows to combine heterogeneous data in a consistent way and to estimate the integrated effect of the attenuated spectrum. In this way accuracy studies can be performed in a general and reliable manner. It is shown that only three second-order gradients contribute significantly to the estimation of the geoidal undulations and that it is sufficient to have gradiometer data in a 5°×5° area around the estimation point. The accuracy of the geoid determination is strongly dependent on the degree and order of the reference field used. An accuracy of about ±1 m can be achieved with a reference field of (12, 12). There is an optimal satellite altitude for each reference field and this altitude may be higher than 300 km for a field of low degree and order. The influence of measuring errors is discussed and it is shown that only gradiometer data with accuracies better than ±0.05 E will give a significant improvement of the geoid. Finally, some results on the combination of satellite gradiometry and terrestrial gravity measurements are given. The proposed method seems to be well suited for local geoid determinations down to the meter range. It is especially interesting for unsurveyed and difficult areas because no terrestrial measurements are necessary. Furthermore, it has the practical advantage that only a local data coverage is needed.  相似文献   

Variability of high rainfalls and related synoptic situations causing heavy floods at the northern foothills of the Tatra Mountains     

Tadeusz Niedźwiedź  Ewa Łupikasza  Iwona Pińskwar  Zbigniew W. Kundzewicz  Markus Stoffel  Łukasz Małarzewski 《Theoretical and Applied Climatology》2015,119(1-2):273-284

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Observations of tectonic microdisplacements in Europe in relation to the Iran 1997 and Turkey 1999 earthquakes     

B. Košt’ák  S. Cacoń  N. D. Dobrev  E. Avramova-Tačeva  E. Fecker  J. Kopecký  L. Petro  R. Schweitzer  A. A. Nikonov 《Izvestiya Physics of the Solid Earth》2007,43(6):503-516

Long-term repeated measurements of microdisplacements in tectonic fault structures of various parts of Central Europe and the Balkan Mountains showed that displacement trends changed significantly at several points in the period from 1997 through 2000; afterward, long-term trends were restored. This phenomenon took place in the periods of strong (M > 7) earthquakes in Iran (1997) and in the North Anatolian fault zone in Turkey (1999). Two strong Izmit earthquakes of 1999 in Turkey at distances of 600 km from the Balkan Peninsula and 1400 km from observation points in Central Europe were the main seismic events of the period studied. Apparently, the crustal deformation due to the sources of the aforementioned earthquakes reaches the central part of the European craton. Anomalous displacements in some areas occurred due to deformation propagating for great distances in the heterogeneous block medium of the West European part of the Eurasian plate. Changes in stresses can be caused by impulsive deformations of various intensities acting on some structural units (fault segments) at various distances.  相似文献