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This paper deals with seismic analysis of RC (reinforced concrete) frame structures without and with shear walls, taking into account the present-days requirements of Eurocode 8 (EC-8). Relevant procedures are presented and discussed referring to the analyses and results taken from two case studies: the first one is a skeleton frame, the second is a dual plane system.

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Authors: M Bielik and P Varga
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The purpose of this work is to investigate how the local soil conditions in the Bucharest area control the ground motion characteristics using all the available acceleration data for large and moderate size Vrancea earthquakes. The proposed comparative analysis shows no systematic variations from one  site to the other in agreement with the relatively uniform subsurface structure beneath the city. The main conclusion of this study is that for the particular case of Bucharest and Vrancea earthquakes, basically the microzonation is emphasizing no areas with significant variation in the amplification factor.  At the same time, the source radiation is clearly controlling the seismic response depending on the magnitude. Thus, for the largest shocks (M w ≯ 7), the seismic response in the range of 1-2 s period is exceptionally enhanced leading to the disastrous damage noticed for the high-tall buildings in the city.

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The problem of site dependent estimation of the seismic strong motion for Sofia region is discussed. Deterministic modelling for micro-zonation of Sofia region is implemented for receiving an estimation of local site conditions as result of displacements provoked by seismic events in Sofia region with  stochastic and neural modelling. An approach for seismic waves classification on the base of principal axis transformation, long-range dependence time series analysis and neural modelling is suggested. With the help of scene oriented model are determined the boundaries of destructive phase of strong motion acceleration. For selected diapason of destructive phase is implemented two-dimensional vector quantization for transformed accelerograms with maximal and middle values. With self-organizing map are determined weight centres of selected classes of destructive phase. Learned and trained self-organizing map optimize selected target classes and  determine probability density function. Suggested model helps to provide side dependent estimation of the seismic strong motion for Sofia region.

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Nowadays natural disasters phenomena as hurricanes, volcanic eruptions, tsunamis or earthquakes, are still difficult to prevent. Based on signaling of the phenomenon imminent appearance in the destructive area, important limitations in human losses and material damages will be carried out. For that  reason, WARNING turned into a key objective, both in theoretical and practical research.  For the earthquakes, warning intervals are nevertheless very short - seconds to maximum one minute (Mexico City case). Even if the time window is reduced, automated decision measures are possible to establish in case of an well organized system, mainly for: protection of dangerous chemical units and oil installations; shutdown valves of the natural gas pipelines to prevent fire hazard; protection of nuclear power plants and other high-risk nuclear objectives; electrical insulating of the power distribution network systems; alerting of emergency services, alerting of civil protection, and particularly of  civil population; protection of railway transportation systems etc.  In Romania, the major seismic risk zone is located in Vrancea region. The earthquakes occurring in this area are the main sources of the seismic hazard on the Romania territory.  Seismotectonic characteristics of the Vrancea region offered the opportunity to create and develop a rapid seismic warning system. This system is simple, reasonably low-priced and robust and allows warning in an approximately 25 seconds time window for Bucharest. Warning signal obtained will be issued at the responsible factors and specific users in order to control automated blocking of the installations and to carry out the required protection actions.

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Authors: Péter Rózsa, Gyula Szö?r, Zoltán Elekes, Bernard Gratuze, Imre Uzonyi and Árpád Z. Kiss

Obsidian samples from different localities of various geologic settings (Armenia, Hungary, Iceland, Mexico, Slovakia and Turkey) were analyzed by particle induced gamma-ray emission (PIGE) technique and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Samples from Mexico and Iceland show higher alkali and REE content as well as higher Nb and Ta abundances than the other samples. Discrimination diagrams show samples from Mexico and Iceland to belong to WPG. The position of the samples from the Tokaj Mts is also definite, and it corresponds to the expectation (VAG or VAG+syn-COLG fields). Using a Li-B diagram the obsidian samples can be distinguished according to their geographic distribution. By means of a Ce-Ti diagram, obsidian from the Tokaj Mts can be divided into three groups that may correspond to the archeometrical C2E, C2T and C1 groups. Phenocrysts in the obsidian samples from the Tokaj Mts, and the Aragats Mts (Armenia) were detected and analyzed by micro-PIXE (proton induced X-ray emission) method. In this way silicate minerals (zircon, pyroxene, biotite, plagioclase feldspars), ore minerals (chalcopyrite, pyrrhotite, pyrite), and other non-silicate mineral (anhydrite) were identified.

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The diversity of the brachiopods in the Northern Caucasus significantly fluctuated throughout the Paleozoic-Mesozoic. Weak diversifications occurred in the Middle Cambrian, Late Silurian - Early Devonian, and Late Devonian - Early Carboniferous. Since the Late Permian brachiopod assemblages became quite diverse. The maximum number of species was reached in the Rhaetian. The Permian/ Triassic mass extinction and enigmatic Ladinian crisis, on the other hand, led to regional brachiopod demises. In the Jurassic - Early Cretaceous interval the diversity of brachiopods generally decreased. The strongest drops of species numbers occurred in the Toarcian and Berriasian following the Pliensbachian-Toarcian and end-Jurassic global mass extinctions, and in the Kimmeridgian due to the regional salinity crisis. It is evident that some of the regional brachiopod diversifications coincided with the development of rimmed shelves.

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At the end of the 1960s scientists of the Geological Institute of the Hungarian Geological Survey described K-enrichments in different rock types exposed at surface in the Western and Central Mátra Mts. At that time these K-rich rocks were not studied in detail. In the framework of a research project we indicated that the main K-bearing minerals are sanidine and orthoclase. The average K2O content of the different potassium-rich rock types reached 9.16%, whereas their K-content is 7.6%. In contrast to previous opinions no direct mineral paragenetic relationship could be established between hydrothermal ore mineralization and the formation of the K-rich rock types. K/Ar data obtained on K-rich rocks indicate that the K-rich rock types are older than the ore mineralization.

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Authors: Sándor Kele, Lászó Korpás, Attila Demény, Péter Kovács-Pálffy, Bernadett Bajnóczi and Zsófia Medzihradszky

In the area of the town of Tata (Hungary) there are several Quaternary travertine outcrops, of which the Porhanyó Quarry is the best-exposed one. The travertine of the Porhanyó Quarry can be vertically divided into six units. Algal and other phytoclastic and phytohermal grainstone, boundstone and floatstone are the dominant microfacies. On the walls of the quarry carbonate vents and cones were detected; these forms are indicators of former spring activity at the bottom of a shallow lake. The lake, fed by thermal springs, was formed in a siliciclastic floodplain. The upwelling thermal water brought quartz and other detrital grains from the underlying Pannonian siliciclastic sediments to the surface, concentrating them in the vents. The three main phases of lacustrine evolution were interrupted first by a drying and flooding event, followed by a fluvial-eolian event and finally by eolian sedimentation. The oxygen isotope compositions of the vents differ from the values of vertical sections and slope samples, whereas the carbon isotope compositions show less variation. The different facies migrated during the evolution of the Tata Travertine Complex due to changes in morphology and flow direction. The integrated model of lake evolution suggests an upward cooling climatic trend, beginning with a humid Mediterranean climate in the early phase and closing with a cold, dry continental one in the late phase. The Tata Travertine Complex shows a marked d13C difference from the travertine occurrences of the Buda Mts. that is attributed to local effects. The ascending solutions at Tata may have infiltrated through organic-rich bedrocks and could have carried dissolved C enriched in 12C.

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Eperkés Hill is a thoroughly studied classic exposure, yet its facies interpretation is still debated. The issue is whether Upper Triassic - lowermost Jurassic carbonates are regular beds or blocks embedded within the Kimmeridgian-Berriasian limestone. The answer to this question is important for the interpretation of the structural evolution and paleogeography of the Transdanubian Range area at the Jurassic-Cretaceous boundary; we decided therefore to contribute to the solution by applying paleomagnetism to the problem.  We tested several regular beds and suspected olistoliths from two artificial exposures. In order to check the consistency of the paleomagnetic signal on site level, we drilled three or more cores from each, and subjected them to standard paleomagnetic laboratory processing and evaluation.  We found that magnetic parameters were distinctly different for "regular" beds and for suspected olistoliths, but that the paleomagnetic signal was consistent within every site. However, between-site consistency was extremely high for regular beds, but was non-existent for the "megabreccia" horizon. Thus, our results confirm that older limestone was moved and re-deposited during the Late Jurassic-Early Cretaceous, indicating geodynamic conditions similar to those in the Northern Calcareous Alps.

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In the densely populated part of Nagytétény bay Metallochemia factory has been operating as a pollution source resulting from stack emission as early as since the beginning of the 1900's. The nearby residential properties were impacted by significant concentrations of heavy metals, which found their way also to the deeper strata of the soil. Our task was to perform the detailed environmental state investigation of the nearly 1,400 impacted properties located in an area of 3.5 km2 and to prepare a technical remediation action plan. For the execution of the task a complex GIS system was developed, to take the numerous design aspects (such as technological and horticultural condition of the objects on the properties, presence of public utilities, current and planned land use, percentage of built-up area, archaeological, cultural, protected natural and other restricted areas, objects, and morphologies, as well as pedological, geological and hydro-geological conditions) into consideration. For the work three series of aerial photographs, taken at different times, and approximately 20 thematic maps with different scales and projections had to be integrated into the system. Data processing was executed by ArcView GIS programme. This system made us possible to manage and evaluate the territorial relationships between the data, as well as to make design calculations, and to thematically represent the results by using previously developed logical functions. On the basis of the design considerations, environmental technical and horticultural remediation action plans were developed for each property. This study presents the main steps of fieldwork and the building of the GIS system without analysis of the collected data.

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Authors: H Schuh, N Panafidina, J Boehm and R Heinkelmann

VLBI observations at various stations all over the globe have been carried out since the beginning of the eighties. As VLBI allows to determine tropospheric parameters such as hydrostatic and wet zenith path delays stable and long time series of these parameters exist that can be used for climatological studies. From the wet zenith delays information about trends and periodic variations of the amount of water vapour in the troposphere can be obtained. For example a trend of ~+0.7 mm/year in the wet zenith delay will correspond to a trend of ~ +0.1 mm/year in precipitable water. For assessing the reliability of the linear trends and the amplitudes of annual and semiannual components, data from VLBI, GPS, and the ECMWF (European Centre for Medium-Range Weather Forecasts) were compared. Good agreement was found for the seasonal variations, though the linear trends showed some disagreement. Possible reasons for this disagreement are discussed. Finally, the effect of El Niño events on tropospheric mapping functions and on length-of-day time series is shown.

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CHAMP and GRACE global geopotential models EIGEN-3p, EIGEN-GRACE01S, GGM01S and GGM01C are compared with terrestrial gravity field data in Hungary. The methods used for comparison were direct comparison with gravity anomalies and the reference geoid solution method. We used free-air gravity anomalies interpolated on a 1' × 1.5' grid covering Hungary. In the second method these geopotential models were used to compute gravimetric geoid solutions and the results were compared with GPS/leveling data from EUVN campaign and the Hungarian GPS network. 

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The study area lies in south Egypt on the west bank of the River Nile about 12 km north to the Aswan City. The aim of the present study is a trial to investigate subsurface structure conditions, to determine the dynamic characteristics of the subsurface rocks and to study the effect of the near earthquake activities on the proposed location of Aswan New City. In this study nineteen seismic refraction P- and S-waves profiles were conducted. The output results include velocities of P-and S-wave and the thickness of each layer. The bulk density of soil layers was calculated from determined P-wave values.  The measured shear wave velocity and bulk density for each layer were used to compute the maximum shear modulus. These parameters for each layer are used as input data to compute the responses of horizontally layered soil profiles subjected to bedrock input motion from strong earthquake using EERA program. The obtained response values of soil layers are represented by the surface acceleration, from which response spectra with damping ratio of 5 % are obtained, surface Fourier amplitude spectra, amplification ratio between rock outcrop and free surface, and the shear stresses and strains characteristics at the sublayer No. 2 in all selected profiles sites. The output of this study is very important for solving the problems, which associated with the construction of various civil engineering purposes and for earthquake resistance structure design.

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The source parameters and dimensions of the tow strongest earthquakes (July 1, 1829, I o = VII-VIII EMS; October 15, 1834,  I o = IX EMS) in Érmellék area are estimated as follows  Date of the event     Focal depth     Magnitude    Rupture area          Max.                                                                                                       displacement July  01, 1829           21-33 km         5.5-5.7         33-55 km2        11-16 cm October 15, 1834     23-28 km         6.5-6.6        266-358 km2      74-90 cm  The average recurrence that we may expect an earthquake of M ≥ 0.7 every 1 year, an earthquake of M ≥ 2.9 every 10 years and an earthquake of M ≥ 5.0 every 100 years in this source zone. The probabilistic seismic hazard assessment predicts 1.1-1.4 m/cm2 peak ground accelerations, and 6.3-7.4 maximum (theoretical) earthquake intensity values with 10 % chance of exceedance for an exposure time of 100 years in the area.

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Estimation of seismic wave attenuation in the shallow crust in terms of coda wave Q structure previously investigated (Sayed et al. 2002) in the vicinity of Cairo Metropolitan area was improved using seismograms of local earthquakes  recorded by the Egyptian National Seismic Network (ENSN). The seismic wave attenuation was measured in the study area from the time decay of coda wave amplitudes on narrow bandpass filtered seismograms on the basis of the single scattering theory. The frequency bands of interest are from 1.5 Hz to 18 Hz. In general, the values obtained for paths and events foci and El-Fayoum (FYM) and Wadi Hagul Sations (HAG) are very similar for all frequency bands. A regional attenuation law Q c = 85.66 f 0.79 was obtained.

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The seasonal frequency of noctilucent clouds has been discussed on the basis of visual data from the Northern Hemisphere. It is shown that there is a strong dependence on the atmospheric constitution at the mesospheric level and the seasonal transition in the mesopause. Before spring transition and after autumn transition of the mesosphere at the 80 km level no NLC are observed on the Northern Hemisphere.  Conversely we can conclude the same distribution for the Southern Hemisphere and the strong relation between transition periods and occurrence of NLC.

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The study area lies in south Egypt on the west bank of the River Nile about 12 km north to the Aswan City. The aim of the present study is a trial to investigate subsurface structure conditions, to determine the dynamic characteristics of the subsurface rocks and to study the effect of the near earthquake activities on the proposed location of Aswan New City. In this study nineteen seismic refraction P- and S-waves profiles were conducted. The output results include velocities of P-and S-wave and the thickness of each layer. The bulk density of soil layers was calculated from determined P-wave values.  The measured shear wave velocity and bulk density for each layer were used to compute the maximum shear modulus. These parameters for each layer are used as input data to compute the responses of horizontally layered soil profiles subjected to bedrock input motion from strong earthquake using EERA program. The obtained response values of soil layers are represented by the surface acceleration, from which response spectra with damping ratio of 5 % are obtained, surface Fourier amplitude spectra, amplification ratio between rock outcrop and free surface, and the shear stresses and strains characteristics at the sublayer No. 2 in all selected profiles sites. The output of this study is very important for solving the problems, which associated with the construction of various civil engineering purposes and for earthquake resistance structure design.

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The understanding of fracture has tended to follow great public disasters (e.g. over 200 US ships suffered due to catastrophic failure during WW II, later several jet air-craft damaged, destroying some bridges and buildings, etc). Rock fracture mechanics dates back to early 60-s and its application to rock  blast problems, collapses deep gold mines in South Africa, earthquake disasters, etc. Pure shear mode (Mode I) or mixed tension and shear mode (Mode I and II) fracturing are the most important in rock mechanics and geophysics. The goal of this paper is to summarize the existing fracture criteria and the observed crack growth firstly from single flaws, secondly from multiply (two) flaws. Analysing the fracture propagations different types of coalescence can be determined and classified. Using these modelling and analysing the observed patterns, for example we could forecast the new failures after the earthquakes or calculating the stability of rock slopes, etc.

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On 28 December 2002, a new boca opened above sea level on the flank of Stromboli. Two days later, a landslide occurred on the same flank, and a tsunami hit the coast of the island. We give an interpretation of such crisis, based on the evidences provided by acoustic emission (AE) records collected at a nearby station, at 160 kHz. The entire set of phenomena, which in general is not linear, corresponded to a paroxysm generated by an anomalous increase of the prime energy breeding of the volcano. The phenomenon involved the entire physical system, and it was manifested in terms of different “catastrophic” events. The final equilibrium was attained when the system was reshaped according to the requirements of its new energy status and balance.

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Three-dimensional gravity modeling has been performed for the Eastern Mediterranean including the northeastern Egyptian off-shore area. The gravity models and seismic profiles indicate that a transition from two layer continental crust to a simple layer oceanic crust takes a place along the Levantine margin. The transition along three profiles is located beyond the north African continental margin and it is quite gradual. The crust under the Levantine basin is typically oceanic and slightly thin with 13 km thickness, however it is typical continental under the Egyptian off-shore and having 30 km thickness. The obtained results reflect a large sedimentary sequence of 14 km under the Levantine basin. Since the sediments recovered by the Oceanic Drilling Program Leg160 in the eastern Mediterranean ranged from Pleistocene to Cretaceous, this reflects fairly high sedimentation rate. Distribution of recent earthquake foci indicates that almost all earthquakes occurred along the western and central segments of the Cyprean arc while they completely disappear along the eastern segment. This means that collision between Cyprus and the Eratosthenes seamount is marked by seismic activity and clearly affects the shape of the Cyprean arc. This collision represents a transition zone between active compression and probable subduction in the western segment and diffuse transtension through the eastern part of the arc. Incipient collision between Cyprus and Eratosthenes seamount probably began in Pleistocene time.

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Seismic coda Qattenuation (Q c) in the frequency range from 6 to 20 Hz of two distinct Scoda windows (early and later portions) are compared to analyse the effects of both coda windows on crustal seismic attenuation estimates around Samambaia fault (João CâmaraNortheastern Brazil). Q cvalues associated with the later portion are systematically higher than those related to the early portion. These values follow a frequency (f) function given by Q c(f) = Q 0 f , where Q 0= 11739 and= 1.000.06. In general, Q 0estimate is less sensitive to site effects and stabler than that obtained from the early portion of S coda waves, while its corresponding frequency dependence is similar to that obtained from the early portion of S coda waves. It suggests thatparameter does not depend on coda window's location along the seismic signal. A comparative analysis of both Q 0andvalues with those found recently shows that there is no difference in using early or later portion of S coda waves in the stations located on Pre-Cambrian basement in the João Câmara area. This comparison also shows that the major variations in Q 0values were observed at seismic stations installed on sedimentary terrain. Differences in the seismic attenuation, in both sides of the Samambaia fault, were also observed in this study, and it is in agreement with the hypothesis that Samambaia fault is a kind of boundary between two seismic attenuation zones.

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Short review on the geophysical application of Ertel's potential vorticity theorem.</o:p>

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Investigated is the relationship between the level of geomagnetic activity and the GPS TEC relative deviations from the monthly medians. Detailed information on this dependence is of crucial importance for developing a new synthetic index which, by quantifying the local response of TEC to geomagnetic activity, will be able to improve the quality of autocorrelation forecast procedures.</o:p>

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Based on the well-known results of classical potential theory, viz. the limit and jump relations for layer integrals, a numerically viable and efficient multiscale method of approximating the disturbing potential from gravity anomalies is established on regular surfaces, i.e., on telluroids of ellipsoidal or even more structured geometric shape. The essential idea is to use scale dependent regularizations of the layer potentials occurring in the integral formulation of the linearized Molodensky problem to introduce scaling functions and wavelets on the telluroid. As an application of our multiscale approach some numerical examples are presented on an ellipsoidal telluroid.

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The time-series ofδ18O values measured weekly in Lake Balaton gave a chance to estimate the period time. To do this, we used a recently worked-out psd estimation method, the Lomb-Scargle periodogram (Lomb 1976, Press et al. 1992), in which the type of distribution can be given exactly to the power values, so confidence interval can be calculated. The result, however, is only a characteristic mean value of the time-interval examined, so the changes of the period-time were examined by demodulation. The essence of the method is that the process (time-series) is let through a filter that is permeable at merely one frequency, all the other frequency components are filtered out, so the difference from the mean period time can be placed in time. We also examined to what extent the water samples coming from one bay of Lake Balaton are representative of the whole lake. Hierarchical clustering was carried out on the hydrobiological and hydrochemical parameters of water samples coming from ten sites of Lake Balaton to determine the similar sampling sites. After the clustering, part of the sampling sites fell into different groups in the examined 16 sampling times. So the groups were marked in all the 16 sampling times with a code that shows to which group that actual sampling site belongs. In this way, each sampling site was placed in a 16-dimension space. Thus, another clustering became possible, so the grouping related to the given time period could be determined. The result was checked by statistical calculations.

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The closed form solution of 7 parameter 3D transformation.The Gauss-Jacobi combinatorial adjustment is applied to solve the 3D transformation problem with 7 parameters, and it is also demonstrated that the combinatorial algorithm gives the same solution as the conventional linear Gauss-Markov model.

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Authors: Gyula Szöőr, Péter Rózsa, Bart Vekemans, László Vincze, Freddy Adams, Imre Uzonyi, Árpád Z. Kiss and Imre Beszeda

Impact material, especially magnetizable tiny grains (spherules, globules and platelets) of Barringer Meteor Crater (Arizona) was studied by combined nuclear analytical techniques. The samples were analyzed first by micro-proton-induced X-ray emission (PIXE) and deuteron-induced gamma-ray emission (DIGE) methods. In this way it was possible to determine the distribution of elements down to carbon. Using micro-synchrotron radiation X-ray fluorescence technique (SRXRF) we could determine medium and high atomic number trace elements such as the platinum-group metals. Our methodological developments made it possible for the first time to carry out quantitative analysis for more than 40 elements, providing new perspectives for the interpretation of the impact materials. Various compositions of the findings around the Barringer Crater were compared to analytical data of similar objects found in Carpathian Basin to elucidate their origin. This paper summarizes the more important results obtained by using ion beam microanalytical techniques.

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We present the results of a fault reactivation study that used the analog modeling technique. The modeled tectonic processes represent the formation and subsequent deformation of the Derecske Trough and have implications for the evolution of the entire Pannonian basin system. Structural inversion of former thrusts led to normal faulting during the Miocene and corresponds to the formation, whereas subsequent reactivation of these faults in a strike-slip manner during the late Miocene to Quaternary represents neotectonic deformation of the basin. Modeling results show that reactivation of thrust faults in a transtensional manner can occur in a broad range of dip angles, and of angular differences between the maximum principal stress axis and the strike of the fault. The reactivation pattern of strike-slip zones in sandbox models critically depends on the orientation of the fault system with respect to the confining stress field, on the material property of the sand, and on the presence of a lubricant layer, representing a potential detachment horizon at the base of the models. The shear zones at the border zones of the Derecske pull-apart basin are prone to further reactivation, regarding the present-day stress field in the area. These inferences are confirmed by the recent seismic activity of the area, and point to the key importance of fault reactivation studies during seismic hazard assessment.

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The Dorozsma Complex (DC) is defined and its main lithologies are described. The complex makes up the bulk of the Algyõ basement high, representing an outlier of a Cretaceous nappe system in the southernmost part of the Tisza Mega-unit (Great Hungarian Plain). The DC exhibits a polymetamorphic history characterized by a Permian, low-pressure amphibolite facies metamorphism, overprinted by a pressure-dominated eo-Alpine, amphibolite facies metamorphism, accompanied by penetrative mylonitization. "Carboniferous breccias" described by earlier authors and covering the metamorphic rocks sporadically are redefined as tectonized, mostly cataclastic rocks. The uppermost unit of the basement below the Neogene sediments is a nappe composed of Triassic clastic and carbonate sediments. Petrographic similarities of the DC with several units of the Koralpe-Wölz nappe system in the Eastern Alps indicate that both units were formed within a continuous belt in the Cretaceous.

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Core samples of metamorphic rocks from the Sarkadkeresztúr Basement High (Békés-Codru Unit, Tisza Mega-unit) were examined, consisting mainly of two-feldspar augengneiss, garnet-andalusite-staurolite-bearing micaschist and paragneiss. The protolith of the plagioclase-microcline-augengneiss was found to be S-type granite (syenogranite) of unknown age. According to the major element analyses the protoliths of the studied metagranitoids of this basement can be classified as a syenogranite of metaluminous and peraluminous character displaying subalkaline affinity and a calcic granitic composition. The REE patterns are characterized by a slight enrichment of the light REEs and negative Eu and Yb anomalies. On the basis of discrimination diagrams for major and trace elements, the studied rocks were formed in a syn-collisional (continent-continent collision zone) tectonic environment. The low-pressure amphibolite facies metamorphism, which affected this basement, can be assigned to the Variscan.

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In the Paleozoic and Mesozoic rocks of the Bükk Mountains the imprints of a polyphase deformation and an anchi-epizonal metamorphism were observed. The physical conditions of this metamorphism were the same as that of the earliest, ductile deformation phase. The imprints of later deformation phases can generally be distinguished by their tectonic style. Our investigation was focused on the style of folding and on the different textural elements of limestone which developed during the early deformation phase. According to lithologic conditions and geographical position, the folds show a certain style variety. The multilayer fold geometry depends on the thickness ratio and the competence contrast between the layers. In the occurrence of different textural patterns the position within a fold and the pre-deformational grain size play an important role. The main deformation mechanism in the fine-grained matrix was pressure solution, while coarse-grained crystal aggregates show signs of dynamic recrystallization, which in some cases leads as far as the development of mylonitic texture and strong lattice-preferred orientation. The differences in spatial style of the same rock types provide a basis for defining tectofacial units in the eastern part of the Bükk Mts.

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In the 1990s detailed geologic exploration in the eastern part of Mórágy Hill (Hungary, southeastern Transdanubia) provided a great deal of new knowledge on stratigraphic features. Making use of and reinterpreting all available geologic data, our study gives an overview of the surface and subsurface extent of the Late Neogene and overlying Pleistocene beds, their stratigraphic position, thickness characteristics, as well as lithology, facies and age. We also cover in detail the stratigraphic position, accumulation type and age of the granite rubble, together with the Tengelic Red Clay Formation, previously unknown in the area. A theoretical section of the characteristics of the Paks Loess Formation is shown, based on the data of Mórágy Hill and the Tolna Hegyhát Hills, defining and describing its lithological units. Using the large number of accurately evaluated borehole sections in the region it could be proved that the Hungarian loess stratigraphy elaborated by the specialists of the Geographic Research Institute could be applied regionally in the Mórágy Hill area as well. Moreover, we offer a detailed classification of loess formations in the area, along with the description of their different horizons. The correlation of the specific horizons of sections allowed us to reveal local differences in formations. These deviations can be explained by one-time environmental differences brought about by local morphologic features and different degrees of exposure, or due to the effect of a more humid microenvironment, long-lasting soil development or slightly coarser parent rocks. On the other hand the absence of loess and/or paleosol horizons in some sections could have been the result of subsequent erosion. Concerning their genetic features, Pleistocene-Holocene fluvial, slide-affected, deluvial and proluvial deposits will be discussed separately.

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The Csódi-hegy laccolith belongs to the Middle Miocene Börzsöny and Visegrád Andesite Formation, and is built up by fluidal amphibole biotite dacite. This is a small, typical laccolith as shown by its size (Dl = 11000-1200 m, D2 = 900-1000 m, A ~ 150 m), shape, areal extent of 1 km2 and aspect ratio of 0.08 to 0.14. The fluidal structure of the laccolith is the result of alternation of dark and light bands. The thickness of the bands is in cm-dm scale. This structure and the feeding channels are very well exposed here thanks to quarrying activity. The time span-calculation was performed by counting of the individual bands, by volume estimations and by detailed magnetostratigraphic study. For the calculation of magma transport and growing-time the following assumptions were made: 6-8 km depth of the magma chamber, pressure of 8-10 kbars, temperature of 850-900 °C, a rate of ascent 1 mm/20-36 hours, 15 cm as the average width of a single band, a relative depth for emplacement about 450 m and the volume of the emplaced body of 0.05 km3. A total of 3150 bands were counted along the 330 m-long key section of the laccolith, from the center of the main feeding channel toward both flanks of the body. In this way the calculated total emplacement time for the formation of the Csódi-hegy laccolith varies between 1,100 and 1,900 years. The final episodic kink stage may range from 3 to 6 years and the cooling stage have lasted about 100 years. Volume estimations resulted in similar time spans, varying between 1,800 and 3,300 years. The rapid change from transitional to reverse magnetic polarity may cover some hundreds to some thousands of years.

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SEM examination of the pelletal phosphates from the Upper Cretaceous of Arief El Naqa in eastern Sinai reveals the presence of bacterial relics and globular clusters of phosphate, iron oxyhydroxides and halite. All have been identified only within cavities and in the phosphatic cement around phosphate particles. These microbial structures were, therefore, produced by the aid of microorganisms in association with infiltrating meteoric water from the nearby vegetation cover. They were able to accelerate the dissolution of pyrite and the leaching of phosphate particles to use phosphorus as a desired nutrient. Phosphate globular clusters and goethite framboids were formed as the result of crystal growth of the biologically precipitated precursor phases. Bacteria were simply available nucleation sites for binding of these nanoparticles. Halite clusters were also identified in a similar setting and show a co-genetic relationship with other types of microstructures. Therefore, the role of microorganisms in the formation of halite microstructures is suggested, but its inorganic origin cannot be totally excluded.

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The Magura Nappe is the innermost tectonic unit of the Western Flysch Carpathians and is linked with the Rheno-Danubian flysch of the Eastern Alps. Toward the east this unit runs as an arc from Austria through the Czech Republic, Slovakia and Poland, and then narrows in Eastern Slovakia before disappearing east of Uzhhorod (Trans-Carpathian Ukraine). The Magura Nappe is dominated by Paleogene deposits. In the Ukrainian Carpathians, SE of the Latorica River, the position of the Magura Nappe is occupied by the Marmarosh Flysch Zone. Two facies-tectonic units have been distinguished in this zone - the external Vezhany and the internal Monastyrets' units. Both the Magura Nappe and Marmarosh Flysch revealed the same geotectonic position, lithofacies development and a similar diachronic distribution of Eocene/Oligocene facies in the basins. The Vezhany succession could be regarded as the equivalent of the Fore-Magura thrust sheet in Poland, whereas the Monastyrets resembles the Rača development of the Magura Nappe in Poland and Slovakia.

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A continuous Sarmatian/Pannonian boundary section, which rarely crops out within the Pannonian Basin, was studied near Oarba de Mures/Marosorbó. Alternating beds of clay marl, calcareous marl, siltstone, sandstone and andesitic tuff are present up to a thickness of about 100 m. Traditionally the Sa/Pa boundary was placed at the top of the last significant tuff layer, which has been confirmed by mollusk-bearing strata a few meters above belonging to the "Lymnocardium" praeponticum Zone. This zone is coeval with the Early Pannonian Mecsekia ultima dinoflagellate zone and the C5r magnetic polarity zone. Three ranks of cyclicity connected to sediment gravity flows are present in the outcrops. Coarse silt to sandstone beds were formed by low-density turbidity currents. These individual events represent "dilution cycles" connected to the intensity and abundance of turbidity currents. Turbiditic beds, some 2-5 m-thick series of sandstones, form coarsening/thickening upward cycles of 8-20 m of thickness. This cyclicity may reflect autocyclic lobe switching in deep lacustrine fans. The lowermost 70 m of the succession comprises a major thickening to thinning cycle, while the uppermost part of the sequence seems to represent a longer turbidite-free interval. The last may either reflect climatically-driven allocyclic lake-level variations or impulses of hinterland structural evolution (tectonic activity vs. quiescence). The background sediments show two sorts of seemingly independent rhythmicity: there is marl with variable carbonate content, occasionally forming a few cm of thickening-upward series of calcareous marl, and it also shows various grades of bioturbation. Calcareous marl is often associated with the appearance of fibrous gypsum laminae. The alternating carbonate content of the marl might be generated either by "production cycles" in the photic zone over which the climatic influence is straightforward, or they were formed as the first products of the evaporite succession from hypersaline bottom waters. The lack of bioturbation combined with gypsum may reveal hypersaline and/or dysaeroabic abiotic bottom conditions. These also indicate that turbidity currents had transported not only terrestrial sediments but less saline, O2-bearing water down to the lake floor, interrupting the biota-poor periods. The salinity of the bottom waters in the deepest basin segments might significantly differ from that of the main water mass, and might have been regulated by the composition and amount of ions dissolved from Mid-Miocene salt diapirs cropping out at the lake bottom elsewhere. Accumulation of hypersaline bottom waters may also be facilitated by climatically-determined density stratification of the lake water.

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It is demonstrated mathematically that the length of the geomagnetic induction vector in the so-called S-interval at any observation site on the surface gives the horizontal derivative of the natural logarithm of the depth below the given site, and not simply the depth as it had been assumed by Ádám and Koppán (2004).

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The annual, monthly, weekly and diurnal distribution of Carpathian and M≯7 earthquakes through out the world have been investigated together with the effect of the Moon. The annual distribution of the M≯7 earthquakes shows long-term stability. The monthly variation of seismic activity in case of Hungarian seismic events over the period from 1964 to 2004 shows remarkable maximum between May and October and a minimum between January and April. In the Carpathian dataset for 1964-2004 characteristic peak were found in the daily distribution around 13h and minimum at 8h and 18h (local time). There was no statistically significant lunar influence detected.

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Authors: A. Ádám, P. Bencze, F. Märcz, D. Martini, G. Sátori, L. Szarka, J. Verő, V. Wesztergom and B. Zieger

This is a summary of the activities of the Geophysics Department of the Geodetic and Geophysical Institute in the framework of the Scientific School Earth Electromagnetism. Ten reports cover the most important topics and emphasize interconnections between the different phenomena. The topics include interplanetary space, magnetosphere and ionosphere, electromagnetic waves in a wide spectrum, and electromagnetic induction, also within a wide range of frequencies and applications. Geomagnetism, especially the Széchenyi István Geophysical Observatory Nagycenk with a lot of different recordings of electromagnetic parameters play important roles in most topics.

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From the very beginning of the magnetotelluric (MT) studies two notions have been coupled to each other: the graphite as one of the causes of strong conductivity anomalies and  tectonics. The graphitic formations of very low resistivity (< 10-1 Wm) are accumulated in the shear zones, thrust sheets, detachment horizon etc.\ and by this way they indicate the tectonics/paleotectonics which may not be indicated by other geophysical method so definitely. The author firstly surveys the manifestation of this phenomenon in case histories of the literature, then illustrates it by own very detailed study carried out on the Transdanubian crustal conductivity anomaly (TCA). The material of the conductor and their possible relation to the seismicity of the area will also be demonstrated by the TCA anomaly. In the closing chapters the origin of the graphite and its accumulation in the shear zones is discussed including the role of the (geothermal) water.

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The investigation of the stability of large objects, such as towers, buildings, bridges, etc.\ without disturbing the function of the object plays a very important role. This paper deals with the problem how Earth tide waves can be used as input signals for this investigation. Two large objects, the TV tower and the church Kecske in Sopron (Hungary) were chosen for tidal measurements. The results prove that tidal signals can be detected and under special circumstances these signals can be used for health monitoring of large objects.

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Based on continuous measurements of the atmospheric electric potential gradient (PG) in the Geophysical Observatory at Nagycenk (Hungary), selected data of the interval 1993-2003 have been analysed. The analyses were particularly aimed at the confirmation of global signatures found by a previous study using PG data of a shorter period. The present results have proved that the seasonal variation of PG (generally showing a winter maximum and a summer minimum at land stations) might really be modified at Nagycenk by a secondary maximum appearing in summer-time of certain years. Further analyses have also been carried out by using data derived from measurements with two different apparatus, however, covering a shorter period. Moreover, a  connection between the occasional summer peaks of PG and the occurrences of warm El Niño periods might also be suggested on the basis of results derived from selected PG data and appropriate MEI Indices showing the time history of the ENSO phenomenon for the interval 1993-2003.

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Authors: J. Závoti, J. Somogyi, J. Kalmár and L. Battha

In the Mathematical Geodesy Division of the Geodetic and Geophysical Research Institute of the Hungarian Academy of Sciences research has been done mainly in two areas: theoretical foundation of the evaluation of geodetic measurements and the practical application of theoretical results. These include interpolation methods, robust estimation, time-series analysis. Results of the research have been applied in areas such as photogrammetry, digital terrain model, polar motion, geodynamics.

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Authors: Z. Wéber, Z. Bus, K. Gribovszki, B. Süle, Gy Szeidovitz and P. Varga

In this paper, research activities at the Theoretical Division of the Seismology Department of GGRI (in short: Seismological Observatory) are summarized. The reported investigations have been carried out since 1999, when the division was founded with three members. Detailed discussions of the presented results can be found in various national and international scientific journals.

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The assessment of the results achieved in our division at the field of physical geodesy is summarised. The studies at the fields of Earth rotation, Earth tides, Earth gravity and the global and regional Earth deformations related to geodesy and geodynamics are presented by citation of the most important publications and dissertations, which cover the history of our institute. The paper ends with the case study related to the newly developed full roving GPS observation strategy.

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At the Geodetic and Geophysical Research Institute of the Hungarian Academy of Sciences the tidal research was started in the mid-sixties of the last century. At first, measurements by horizontal pendulums (Tomaschek-Ellenberger, Melchior) were carried out. At the beginning of the 70's a new horizontal pendulum with capacitive transducer was developed. By means of this pendulum tidal measurements were carried out at the Geodynamical Observatory in Sopronbánfalva and local geodynamical movements were monitored in a coal mine in Pécs and at our nuclear power plant in Paks. At the beginning of the 90's a quartz tube extensometer with capacitive transducer was installed at the Geodynamical Observatory in Sopron and in the uranium mine in Pécs. The extensometers in Budapest installed in the early 80's, the extensometer in Výhne (Slovakia) were mounted with capacitive transducers. New, in-situ calibration method was developed at our institute and all of these extensometers were recalibrated by the new calibration device.  A microbarograph of high resolution was also developed for the study of atmospheric tide in 1991. The investigation of the connection between air pressure variations and geodynamical phenomena has been carried out since 1992. This paper presents the developed instruments and the results obtained by these instruments.

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The source parameters and dimensions of the three most important earthquakes (Zsolna - Jan. 15, 1858, I o = VIII EMS; Jóko - Jan. 9, 1906, I o = VIII EMS; Jóko- Jan. 16, 1906, I o = VII-VIII EMS) of the area studied are estimated as follows: Event (Magnitude, Rupture area, Max. Displacement); Jan. 15, 1858 Zsolna (5.5 Ms, 22-36 km2, 8-11 cm); Jan. 9, 1906 Jóko (5.7 MS, 40-55 km2, 12-16 cm); Jan. 16, 1906 Jóko (5.3 MS, 12-24 km2,4-8 cm). The average recurrence that we may expect an earthquake of M = 2.3 every 1 year, an earthquake of M = 3.7 every 10 years and an earthquake of M = 5.1 every 100 years in this source zone. The probabilistic seismic hazard assessment predicts 1.2-1.7 m/sec2 peak ground accelerations, and 6.6-7.2 maximum (theoretical) earthquake intensity values with 10% chance of surpassing for an exposure time of 100 years in the area.

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Systematic earthquake data collection in the Pannonian region started early in the nineteenth century. Officially organised collection and evaluation of earthquake data started in 1881 when the Permanent Earthquake Committee was founded within the Hungarian Geological Society. We can regard this Committee as the ancestor of the Seismology Department of the Geodetic and  Geophysical Research Institute (GGRI). Today the Observatory Division of the Seismology Department of GGRI (in short: Seismological Observatory) gathers instrumental and macroseismic earthquake data and also deals with determination of earthquake focal parameters, among other tasks. The Seismological Observatory operates 7 stations in the country. Six of these stations are very broadband ones with near real-time accessibility of data. Based on the national seismograph station network and also integrating data from agencies of neighbouring countries our Division localises 80-100 local earthquakes annually. The relatively numerous localised earthquakes serve a base for, among others, crustal structure studies and also for more precise earthquake hazard evaluation.

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In the contact zone of three tectonic units (Pannonian Basin, Eastern Alps and Dinarides), in a complicated - basin and range - geological situation magnetotelluric deep soundings were carried out along a 140 km long profile\linebreak (CELEBRATION-007) with a site distance of 2 km. In this area deep fractures of the Basin run together in NE-SW direction. In the paper various magnetotelluric images completed with gravity and magnetics are provided. In the traditional magnetotelluric approach, the structural indication of the TM and TE mode magnetotelluric sounding curves is clearly separated. The TM mode curves well express the resistive basement structure, already known from dense boreholes and detailed seismic exploration. The TE mode curves on the other hand (together with the induction vectors of very low values) definitely show the conductive root of the deep fractures, where the ductile materials are assumed to be raised into a very shallow depth of about of 8 km. The high heat flow of the area (about 100 mW/m\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $^2$ \end{document}), which explains the shallowness of the conductive asthenosphere is also well indicated. The asthenosphere has more Alpine character in the NW part of the profile (its depth is about 80 km) and it is at smaller (about 50 km) depth in the SE part  of the profile, due to the higher heat flow near the extensional Drava Basin. The induction vectors are also separated into two characteristic regions, according to their general direction, influenced by both local and remote effects. A strong correlation is shown between magnetotelluric and gravity inversion results. A joint interpretation of magnetotelluric, gravity, magnetic results provide a quite comprehensive interpretation about the deep geological structures in SW-Hungary.

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The Internal Dinarides include ten larger allochthonous pre-Alpine complexes, similar in many respects to those in the Eastern Alps, Carpathians and Rhodopes. The Dinaride Paleozoic complexes consist mainly of Devonian to Permian formations and are commonly associated with abundant Triassic sediments. In addition, the largest Paleozoic complexes contain subordinate Cambrian-Ordovician formations. The best developed Early Paleozoic complex, which occurs in western Macedonia, is composed of fossiliferous Cambrian metasediments with ophiolites and fossiliferous Ordovician metasediments, interlayered with subordinate metavolcanics and intruded by coeval Ordovician granitoids (461-465 Ma) that were overprinted during the Variscan and Alpine tectonogeneses. It is underthrust by Variscan formations and overthrust by Neoproterozoic Pelagonide formations. Parts of the Paleozoic Drina-Ivanjica complex are composed of fossiliferous Cambrian-Ordovician metasediments containing metamafics and metatuff that were overprinted by Early Cretaceous metamorphism. In the Mid-Bosnian Schist Mts, formations of presumed Cambrian- Ordovician age characteristically consist of gneiss and amphibolite, which can be compared to the Oetztal complexes of the Eastern Alps. Dinaridic Cambrian-Ordovician formations from all three areas were metamorphosed during the late Ordovician deformation under P-T conditions of greenschist and, to a lesser extent, epidote-amphibolite facies (400-500 °C and 4-5 Kbar). Based on geochemical data, Ordovician bimodal volcanics and granitoids indicate a geotectonic setting comparable to recent back-arc basins.

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Permo-Triassic rift-related magmatism in the Dinarides produced an intrusive gabbro-diorite-syenite-granite formation and an extrusive basalt-andesite-dacite formation with abundant pyroclastic rocks. They are spatially and genetically related to Late Permian to Norian rift-related sedimentary formations of the Adriatic-Dinaridic carbonate platform (ADCP). The volcanic and pyroclastic rocks are interlayered with fossiliferous sediments that range between the Late Permian and Middle Norian; the plutonic rocks, which are intrusive into Late Paleozoic and Scythian-Anisian sediments, have radiometric ages ranging between 262 and 212 Ma. Based on major and trace element contents, rocks of the Permo-Triassic magmatic association originated by fractional crystallization from primitive alkalic basalt to olivine tholeiite melts. Volcanic rocks were affected by strong ocean-hydrothermal metamorphism. Initial 87Sr/86Sr ratio of 0.703 and d18O of 5.6‰ of the most primitive rocks indicate an upper mantle origin. Most initial 87Sr/86Sr ratios range between 0.704-0.707, indicating a slight degree of crustal contamination. The Permo-Triassic igneous rocks of the Dinarides represent a specific and autonomous paleorift-related association, which cannot be correlated with the magmatic associations either from recent oceans or with alkali rocks from the Cenozoic African rift and Permian Oslo graben.

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Authors: Sándor Kovács, Péter Árkai and János Haas