# Euler, the theory of gravitation and some geophysical aspects

Authors: W. Schröder and H.-J. Treder

Euler's results concerning the theory of gravitation are discussed in this paper in order to give an insight into the scientific problems of Euler's age and his relation to Newton's work. Geophysical aspects are emphasized in his work.

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# Evolution of angular momenta and energy of the Earth-Moon system

Author: A. I. Arbab

We have developed a model for the evolution of the Earth-Moon angular momenta, energy dissipation and tidal torque valid for the entire history of the Earth-Moon system. The model is supported by present observational data.

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# Filtering of earth's polar motion using trigonometric interpolation

Author: J. Géza Závodszky

The annual wandering of Earth's pole takes place in an area about 200 m2. Within this area, the amplitudes of the displacements due to Earth tide and global meteorological processes do not exceed a few decimetres. Obviously, very precise measuring technique is necessary for the examination of the above phenomena. Nowadays, these are primarily the devices and the methods of cosmic geodesy. From them, on the basis of Ádám (1990) the VLBI (Very Long Baseline Interferometry), and the SLR (Satellite Laser Ranging) are able to show the variations of the pole with periods between one day and one year. The GPS (Global Positioning System) and the developed processing system of VLBI are suitable for the examination of processes within a day.

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# First step towards specification of plasmaspheric-ionospheric conditions over Europe on-line

Authors: L. R. Cander and L. Ciraolo

The paper describes a procedure of the ionospheric total electron content (TEC) specification on-line over Europe intended to provide the vertical total electron content in an operational environment. TEC data are derived from the International Global Positioning System (GPS) Service for Geodynamics (IGS) signal phase and amplitude measurements at European ground station network. Specification here refers to the fusion and visualization of available observations into a map representation of the plasmaspheric-ionospheric state over Europe with a maximum delay of up to about 24 hours. It is designed for models of operations that include post-analysis and real-time.

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# Focal depths of earthquakes in the Carpathian Basin

Authors: Gy Szeidovitz, Z. Bus and K. Gribovszki

Analysing the areal distribution of earthquakes produced in the Carpathian Basin the conclusion can be drawn that only certain parts can be considered active along fracture lines, namely those parts which separate individually moving blocks. Generally accepted working theory states that if one fracture line ever generated an M-magnitude earthquake then at any point of the same line a similar or larger tremor may happen again. However, this principle is not supported by domestic experiences. In accordance with focal depths analysis we are going to verify that earthquakes were produced within more or less consolidated layers inside subsiding basins. Our analysis is aimed to explain the possible origin of earthquakes within small depth range and to point out the practical benefit of these investigations. We present also an analysis on the possible origin of „basin tremors” not taken so far into consideration and we offer a plausible explanation. Uncertainties of focal depth (hypocenter) determinations will also be given and we define relations between the focal depth (h), the magnitude (M), and the epicentral intensity (Io). The result will be presented in tables and comparison will be given between the focal depth data determined by us and by others. Finally viewpoints will be presented to help the recognition of earthquake foci and to set earthquake hazard determination on a real basis.

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# Frequency of occurrence of auroras at middle latitudes

Author: W. Schröder

A compilation of German auroral observation data for 1949-1964 is given. The observations are analysed with respect to the K p-index and seasonal variation. The appendix contains a full list of these observations.

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# The general relativistic and covariant form of the I. Helmholtz vorticity theorem and geophysical application

Authors: W. Schröder and H.-J. Treder

The general relativistic and covariant differential form of Helmholtz's first vorticity theorem is presented. We prove in relation with it an invariant kinematic identity which is the generalisation of the Helmholtz theorem for general continua.

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# Generalization of spline interpolation for geodynamic models

Author: J. Závoti

Závoti (2002) presented the mathematical description of the interpolation method especially for modeling the orbit of artificial satellites, which is suitable for approaching only certain 9 points. The task in this form stems from Grafarend and Schaffrin's (1993) study. During the time passed since the elaboration of the method, the generalization of the algorithm became necessary in the case when we have an arbitrary amount of measurement points, which must be approached according to a certain principle. The generalized method was successfully applied for modeling geodynamical processes, for describing the motion of the Earth's poles and for analyzing economical  time series.

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# Geonomy - in relation to the Solar System

Author: Erzsébet Illés-Almár
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# Georg von Neumayer (1826-1909) and international geophysics | A case study with special remarks on geomagnetic research

Author: K. H. Wiederkehr
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# Gravitational viscoelastodynamics

Author: D. Wolf

We consider a compositionally and entropically stratified, compressible, rotating fluid earth and study gravitational-viscoelastic perturbations of its hydrostatic initial state. Using the Lagrangian representation and assuming infinitesimal perturbations, we deduce the incremental field equations and interface conditions of {\em gravitational viscoelastodynamics} (GVED) governing the perturbations. In particular, we distinguish the {\em material}, {\em material-local} and {\em local} forms of the incremental equations. We also demonstrate that their short-time asymptotes correspond to generalizations of the incremental field equations and interface conditions of {\em gravitational elastodynamics} (GED), whereas the long-time asymptotes agree with the incremental field equations and interface conditions of {\em gravitational viscodynamics} (GVD). The incremental thermodynamic pressure appearing in the long-time asymptote to the incremental constitutive equation is shown to satisfy the appropriate incremental state equation. Finally, we derive approximate field theories applying to gravitational-viscoelastic perturbations of isocompositional, isentropic and compressible or incompressible fluid domains.

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# Gravity inversion techniques for High-Low SST applied to a simulated GOCE orbit

Authors: L. Földváry and M. Wermuth

The paper gives an overview of recently considered concepts and methods for gravity inversion from the orbit of a Low Earth Orbiter (LEO). In this study only noiseless simulations were performed. The study aims to introduce these methods and to demonstrate their feasibility for High-Low Satellite-to-Satellite Tracking (SST) concerning the forthcoming GOCE satellite. Further conclusion on the efficiency of these methods within the scope of this study will not be provided.

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# Heavy mineral assemblages of Senonian formations in the Transdanubian Range, Hungary

Authors: Gizella B. Árgyelán and Horváth Péter

The heavy mineral assemblages and chemistry of detrital spinel grains from the Senonian basin of the Transdanubian Range (TR) were examined and compared with previous results from Jurassic and Lower Cretaceous successions of the Gerecse Mountains of the Transdanubian Range Unit. The heavy minerals recorded that in the area of Transdanubian Range the sedimentary cover, low-grade metamorphic and granitic rocks of the continental crust were eroded in the Coniacian and Santonian. Detritus of high-grade metamorphics was transported to the bathyal basin during Campanian time. The ophiolitic source area indicated by the presence of chrome spinel, ilmenite and magnetite still existed and persisted through the Late Cretaceous.  Compared to the low TiO2 content (lower than 0.2 wt%) of detrital spinels from Jurassic and Lower Cretaceous sediments of the Gerecse Mountains, the most characteristic features of spinels in the Senonian sediments are as follows: exceptionally high TiO2 content (about 0.5-4.7 wt%), relatively high amount of Cr2O3 (about 33-50.8 wt%) and high total iron (sumFeO=15-36 wt%). The data on detrital spinels from the Ajka Coal and Csehbánya Formations suggests that xenoliths (mainly dunites), which previously enclosed the spinel grains, may have been formed from alkalic-tholeiitic magma as crystal accumulates. This was the potential source rock of high TiO2-bearing spinel grains.

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# Heterogeneity analysis of clastic sediments by computerized X-ray tomographs

The CT technique is unique because it provides a non-destructive evaluation of sedimentary rocks. The absorption of X-radiation, emitted by a high-voltage generator, depends on the bulk density and atomic weight of the substance. The lower the density of the material, the more transparent it is to X-rays. If the emitted energy is constant, the absorption depends only on the density of the substance, which is represented by different Hounsfield Units. In case study No. 1, a pelitic core sample of an ox-bow lake environment was analyzed. The mathematical-statistical estimates and significant time-series model (ARIMA) proved that the data coming from the CT images show the presence of micro-cycles. The applied method proved the influence of seasonal floods on local sedimentation. In case study No. 2, the data represent a younger and an older Bouma sequence. The macroscopic study suggests that there are two C units in the core, because an erosional surface is clearly identifiable between the older and the younger units. This case study shows the necessity of precise sedimentological knowledge in addition to that of mathematical-statistical methods and software, and that an accurate macroscopic study is essential and never replaceable. Also, it should be kept in mind that it is often reasonable to replace the conventional statistical conception with a geostatistical approach. The aim of this study was to demonstrate a “non-traditional” strategy in sedimentology and the interpretation thereof.

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# How magnetotellurics is able to see through 3D near-surface inhomogeneities?

Authors: L. Szarka, D. Zhang and A. Ádám

In order to investigate imaging properties of various magnetotelluric interpretation parameters over complicated models, we carried out numerical model calculations, where the models contained a 3D near-surface (shallow") part and a 3D or 2D deep part. Various alternatively defined magnetotelluric responses, all of them based on rotational invariants of the magnetotelluric impedance tensor were considered. Then we calculated correlation coefficients between all these MT responses, and the characteristic geometrical parameters of the subsurface models, considered as a composition of “shallow+deep” elements.A systematic behaviour, similar to that had been observed in 1D situation was found: det(Re Z), Re det(Z) based apparent resistivity has the largest depth of  investigation and the best lateral resolution. Furthermore, besides the phase, the Re det(Z) (a twin-parameter of the phase) seems to give the most direct response about deep structures. In presence of 3D near-surface inhomogeneities the most surprising result is that there are narrow period windows, where the deep model can be directly seen in the Re det(Z) and in the phase responses.

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# The importance of remote sensing techniques in surface geologic mapping

Authors: Zoltán Unger and Ferenc Síkhegyi

The role of remote sensing is well known and can be successfully applied as an initial step in surface geologic exploration. The aim of this study, by means of Landsat TM 7 image interpretation, is to assist photogeologic map compiling, which will serve as a core document for an upcoming field mapping exercise. The mathematical background and the wide variety of math-method possibilities offered by a satellite image interpretation software were used for this purpose. In this way the requested preliminary photogeologic map was compiled, based on the spectral properties of the surface geologic formations. Fortunately the areas of interest were in a desert area (Central Libya), so there was no limitation by vegetation coverage to hinder the application of spectral properties to geologic formations. After the geocoding of the images the display of different compositions of the Landsat TM 7 registration channels was begun. Contrast enhancement and histogram fitting were applied, and further operations to highlight some hidden properties of the original dataset were performed. Thus, some filters from the set offered by the software, some edge enhancement and finally the two types of classification (unsupervised and supervised), were applied.

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# In memoriam of professor Paul Melchior (1925-2004)

Author: P. Varga
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# In memoriam professor László Cserepes (1952-2002)

Author: F. Horváth
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# The influence of high latitude off-great circle propagation effects on HF communication systems and radiolocation

Authors: E. M. Warrington, A. J. Stocker and N. Y. Zaalov

A wealth of knowledge resulted from the investigations into gross deviations from the great circle path (GCP) outlined below.  The magnitude and variances of the deviations from the GCP have been quantified and the associated geophysical conditions and signal characteristics identified.  Research is currently being undertaken aimed at incorporating the knowledge gained from the experiments into techniques that will be of direct operational application.  The main activities in this area include the development of ionospheric models coupled with ray tracing studies (some preliminary results of which were presented here) both to confirm the cause of the large bearing deviations and to assess the impact of the presence of the high latitude ionospheric features causing the deviations on paths other than those subjected to experimental investigation.

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# The influence of lower-boundary condition on the groundwater flow system

Author: János Szanyi

Modeling is essential for the investigation of material-energy transport processes below the surface. During the construction of groundwater flow models hydraulic conditions are usually not considered below the investigated space. The boundary conditions are mostly fixed at the border; i.e. there is no flow across the boundary. However, this condition is not tenable in every case, so its practical applications may lead to false conclusions. The present paper shows how the flow geometry changes with the modification of the lower-boundary condition and fault zone conductivity in a study area near Debrecen, NE Hungary.

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# Initial GPS radio occultation measurements of the ionosphere onboard CHAMP

Authors: N. Jakowski, A. Wehrenpfennig, S. Heise and et al.

The radio limb sounding or occultation technique is capable of deriving accurate vertical profiles of atmospheric refractivity. This has been shown by very promising results of the first active GPS limb sounding GPS/MET experiment on Microlab 1. In this paper we report early results of ionospheric radio occultation (IRO) measurements carried out onboard the German satellite mission CHAMP (CHAllenging Minisatellite Payload) that contributes also to essential improvements of gravity and magnetic field models of the Earth.  First radio occultation measurements of the ionosphere were carried out by CHAMP on 11 April 2001.  Fortunately, ionospheric radio occultation measurements were switched on during the High Rate GPS/GLONASS  measuring campaign (HIRAC) initiated by the International GPS Service (IGS) and supported by COST 271 activities. So a comprehensive analysis of coordinated measurements will be possible within COST 271 cooperation in the near future.  The achieved accuracy of the retrieved electron density profiles is estimated by comparing them with independent ionosonde data.

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# Integrated Palynology of the Upper Cretaceous in Crimea, Ukraine

Author: Ágnes Siegl-Farkas

The author provides new data for the paleontological and stratigraphic understanding of the Upper Cretaceous formations of the Crimean Peninsula. Within the classic Bakhchisaray region 24 samples from six sections (Cenomanian-Maastrichtian) were studied. About 130 palynomorphs have been identified, 11 associations (spore-pollen and dinoflagellate) were differentiated and correlated with nannozones, foram zones and macropaleontological zones. The study confirms that during the Senonian the Crimean Peninsula belonged to the northern nearshore-neritic region of the Tethys and on land to the boreal Normapolles Phytogeographic Province.

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# Investigation of ground and object motions at the TV tower in Sopron, Hungary

Authors: G. Mentes and M. Fabian

The investigation of the coupling between building and ground motions is of great importance because the results contribute to the planning of stable, motionproof constructions and to forecast of damages. For monitoring ground and building motions the TV tower in Sopron, Hungary was chosen. Two borehole tiltmeters, Applied Geomechanics Inc., model 722A were used for continuous and short-term high frequency tilt measurements. One of the instruments was installed on the concrete basement of the TV tower and the other in a borehole drilled at a distance of about 90 m beside the tower. This paper presents continuous data series of a length of more than one year, high frequency tilt measurements with sampling rates of up to 10 Hz and discusses the first experiences of the observations.

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# Ionospheric data combination as a way to improve electron density estimations

Authors: M. García-Fernández, M. Hernández-Pajares, J. M. Juan and et al.

Several approaches have been made in the context of data assimilation in order to improve the estimates of electron density. The key point is to combine different types of data that offer complementary information, thus allowing to obtain a three dimensional description of the electronic content of the ionosphere. In this paper a data assimilation scheme will be proposed in which the complementarity of information will be given by the ground GPS data (horizontal variation) and vertical profiles  derived from ionosonde data (vertical variation). The results of this assimilation scheme will be verified by an external source of data, the GPS data gathered from receiver onboard GPSMET, a low earth orbiter at 750km. This comparison will show the feasability of this assimilation scheme. Moreover it will be shown how this method is able to provide with valuable information about the topside ionosphere by means of comparison with the vertical profiles retrieved from Radio Occultations using  Abel inversion. To do this  the approach of Abel inversion based on a separability hypothesis will be explained, and it will be compared with the classical approach that assumes spherical symmetry.

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# Ionospheric scintillations modelling by MPS and MPC phase screens methods

Author: N. Caouren

GPS navigation and SAR imaging systems performances depend on correct characterization of perturbations due to electromagnetic wave propagation through turbulent media such as ionosphere or troposphere. At these systems frequencies, ionospheric scintillations, which are more or less important according to geophysical conditions, must be studied as well as mean perturbations due to medium crossing.  After a description of ionospheric parameters, existing scintillation models are presented. Then, MPS and MPC numerical phase screens methods developed to simulate time series representative of ionospheric scintillations are described. These methods, which are applicable whatever the temporal and geographical localizations are, evaluate scintillation parameters close to analytical theoretical ones. Several  propagation conditions can be simulated such as propagation of a wide band source signal  or wave propagation through bidimensional anisotropic screens.

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# Iron-rich reevesite from the Ni-Fe ores of Mt. Radocelo, Serbia, a possible new member of the hydrotalcite subgroup

Authors: Zoran Maksimovic, György Pantó and Géza Nagy

The Ni-Fe ores represent the reworked part of the Paleozoic weathering crust on ultramafics. Talcose serpentinite, with a small accumulation of Ni-talc, represents the lowermost part of the destroyed weathering crust. XRD and EPMA study of the ore revealed its complex composition: magnetite is most abundant, with cores of detrital chromite; Ni-chlorite is also abundant; talc, goethite, hematite, maghemite, magnesite and Fe-rich reevesite occur in variable amounts. XRD of the ore revealed weak reflections of reevesite, with the strongest at 7.60 Å. Nine electron probe analyses of this mineral were performed. The richest in nickel gives the following recalculated formula: (Fe2+ 4.03 Ni1.97)6.00 (Fe3+ 11.96 Al0.03 Cr0.01)2.00 CO3 (OH)16 . 4H2O. According to this composition, the mineral is the Fe-analog of reevesite and a new member of the Hydrotalcite Group.

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# Isoseismal map and tectonical position of the Komárom earthquake of 1763

Authors: Gy. Szeidovitz, R. Gutdeutsch and Péter Varga

The seismicity of the Pannonian Basin is not yet understood. To improve our knowledge in this field the geological position as well as the damages caused by the biggest known earthquake of the inner part of the Pannonian Basin, i.e. the Komárom earthquake of 1763 was investigated. It is shown that this earthquake had probably an epicentral intensity of 9.5 MSK, and its origin was in connection with the Rába-Hurbanovo tectonic line.

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# József Verő, the Editor-in-Chief is 70 years old

Authors: A. Ádám, L. Szarka, Á Wallner and B. Zieger
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# Kepler and gravitation

Authors: W. Schröder and H.-J. Treder

Some aspects of Kepler's contribution to the explanation of the law of gravitation are discussed with a historical background. The transition from Keplerian to Newtonian ideas is explained.

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# Late Quaternary geohistory of Sárrét Basin, based on studies on core Sárrét-2, Hungary

Authors: Tibor Cserny and Pál Sümegi

The Sárrét marshland is situated along the northeastern foothills of the Bakony Mountains, along a NE-SW-trending neotectonic zone. Investigation of the marshland and the reconstruction of its evolution are especially interesting to compare to the present and the expected future stage of Lakes Balaton and Velence. Based on the sedimentological characteristics of the core sequence and the geochemical, physical, and mineralogical composition of the layers, three sedimentological cycles could be separated. The three cycles represent the most important evolutionary phases of lake formation: flourishing and progressive aging. First, a nutrient-poor, open-water lake existed, where clastic sediments (sand and silty clay) were deposited. During the second phase, phytoplankton-produced autogenic lime mud was deposited in the progressively more eutrophic water. Peat accumulation during the third stage indicates the marsh phase of the lake.The results suggest that the studied sequence developed from Late Glacial to Middle Holocene. According to radiocarbon dating the accumulation rate in Sárrét (Sümegi, this volume) corresponds to the sedimentation rates in the Tapolca Basin and Lake Balaton.

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# Lithosphere in the Western Carpathians and its surrounding tectonic units - Geophysical study

Authors: M. Bielik, J. Šefara, M. Kováč, J. Hók, J. Vozár and H. Zeyen

Geophysical methods are important tools for the investigation of the structure and geodynamic development of the lithosphere. The central and eastern parts of the Western Carpathians are bordered in the north by a thicker  and stronger lithosphere of the European platform (100-150  km), which is underthrust (about of 50 km) beneath the margin of the overriding Carpathian orogen. This thickening is interpreted as remnants of subducted slabs. In contrast, the “thin” lithosphere at the western margin of the Western Carpathians can be considered as a result of oblique collision along a deep-seated transform zone between the platform and orogenic lithosphere. Neo-Alpine “soft” collision and retreating subduction of this orogen can also be discovered by means of quantitative interpretation of observed gravity field. The crustal thickness in the Western Carpathians ranges among 27-35 km. The central Western Carpathians are characterized by thicker crust (30-55 km) in comparison with thinner crust (25-30 km) in the Pannonian Basin System. This feature is probably the result of the youngest lithosphere processes from the Middle Miocene. Rheological properties of the Western Carpathian lithosphere show that the mechanical strengths decrease within the whole lithosphere from the area of the European platform via the Western Carpathians to the Pannonian Basin. The most remarkable and important first-order tectonic structures (seismo-tectonic zones) in  the Western Carpathians are the zones of the Pieniny Klippen Belt, the Mur-Mürz-Leitha fault zone, the Čertovica fault zone and the Hurbanovo line. Map of neo-Alpine fault systems and neotectonic regions (blocks) of  Slovakia was defined.

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# Local seasonal gravity changes in the lower rhine embayment, Germany

Authors: Keysers, H-J. Kümpel and J. Campbell
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# Localisation and direction determination of fissures with geoelectric methods in narrow, elongated measuring areas

Authors: S. Szalai, M. Abd Alla, S. Ahmed and et al.

In this paper we provide a field example for the determination of the location and direction of fissures in narrow, elongated measuring areas. The test measurements were carried out on the Mokattam plateau at Cairo (Egypt). Direction, length of the layout and the profile length all were very limited, since the measurements had to be carried out within a narrow (2-10 m wide) stripe, between a built-in area and a cleft rim. Interpretation of field measurements was supported by (1) analogue model experiments, and (2) parameter sensitivity maps. As it was found from laboratory experiments, fissures are indicated by potential-difference maximums along profiles measured by using three-electrode array (if the reference point is between the potential electrodes). The mean distance between two neighbouring maximums throughout the whole profile was found to be about 3-4 m, corresponding to the distance between the most visible fissures on the cleft wall. The Schlumberger null-array has been found to be an appropriate tool in determination of the direction of fissures. Its resolution is higher than that of the classical Schlumberger array. Its only disadvantage is that on the azimutal diagram it gives two times more minimum pairs than the number of fissures. Among such constrained circumstances the best method to get useful information about location and direction of fissures in the subsurface limestone is to use jointly corresponding traditional and null-arrays. While the location is given best by traditional three-electrode array measurement, the direction of the fissures is given from the joint interpretation of the Schlumberger null-array and the traditional Schlumberger array. In this way it is to separate several fissure directions.

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# Long period electromagnetic induction vectors in a sedimentary back-arc basin (Carpatho-Pannonian Basin)

Authors: A. Ádám and A. Koppán

Two effects have been studied concerning the former Wiese arrows and the newly determined complex induction vectors in the Pannonian backarc basin (Hungary): the remote effect of the curved Carpathian Conductivity Anomaly (CA) on the direction of the long period vectors, the local effect of the thickness (or conductance) of the conductive sediments on the induction vectors. The curvature of the Carpathian CA is clearly seen in the direction of the induction vectors as a remote effect dividing the Pannonian Basin into two great parts from this point of view. Following Zhang et al. (1993) who stated that the length (absolute value) of the induction vector becomes also constant in the “S-interval” as the magnetotelluric (MT) impedance which is related to the conductance of the sedimentary cover, it has been studied whether there is also any relation between the length of the induction vectors and the conductance of the same sedimentary cover (or thickness of sediment if its resistivity is constant). Due to the structural inhomogeneities to which the induction vectors are very sensitive, and to their great remote (side) effect, only a weak statistical relation has been found, nevertheless, its trend could be approximated by Ritter and Banks' (1998) theory. Exceptional cases are demonstrated.

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# Lower Miocene lakes of the Balkan Land

Authors: Nadežda Krstić, Ljubinko Savić, Gordana Jovanović and Elvira Bodor

The sea existing till the end of Oligocene was dotted with many islands in what is today the Balkan Peninsula area. At the very beginning of the Miocene this region became dry land, the Balkan Land, which was covered through time by lake systems of variable extent. During the Lower Miocene a succession of three lake systems spread not only over the Balkan Peninsula (comprising ex-Yugoslavia, NE Macedonia, SW and SE Bulgaria, and central Greece) but also over the northern parts of the Central and some of the Western Paratethys. Lacustrine environment ended shortly after the beginning of the Middle Miocene, when waters of the epicontinental Paratethys Sea covered the Balkan Land from the north. In this paper we do not consider any of the Upper Miocene and Pliocene lakes.

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# Magmatic garnet in deformed aplite dykes from the Mórágy granitoid, SE-Transdanubia, Hungary

Authors: Edit Király and Kálmán Török

This paper is devoted to the description of spessartine-almandine garnet (Sps: 39.8-60.2%; Alm: 29.1-56.76%; Grs <7%, Prp <3.6%, Adr <5%) from aplitic dyke rocks of the Mórágy granitoid near Erdõsmecske and Aranyos valley. The aplitic dyke rocks contain K-feldspar, plagioclase, quartz, (myrmekite), ±garnet, ±biotite, chlorite or secondary muscovite, ±ore minerals, ±calcite, ±apatite and ±epidote. Two different zoning types in garnet were detected by electron microprobe. Zoning type I means either Mn enrichment at the expense of Fe towards the rim or towards the core or plateau garnet profiles. Zoning type II displays Ca enrichment at the rim of garnet. A high proportion of Sps component in garnet and the character of zoning type I are considered as typical magmatic features.  The pressure-temperature estimation for aplite formation arises from experimental investigations of Green (1977) in agreement with the hypothetical approach of liquidus relationships by Abott and Clarke (1979) giving a minimum temperature estimation of c. 675 °C-700 °C at pressure of 1-3 kbar. Following the magmatic crystallization, solid state deformation is evidenced by dynamic recrystallization of quartz and feldspars at temperatures of about 450-500 °C in the upper greenschist to lower amphibolite facies. Grossular-rich rim of garnet indicates pressure increase during ductile deformation.

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# Micromorphology and mineralogy of the Eocene calcrete gravel from the Mecsek Mountains (S Hungary)

Authors: Andrea Varga, György Szakmány and Béla Raucsik

Redeposited Eocene calcrete gravel was found in a Miocene conglomerate sequence in the Western Mecsek Mountains, S Hungary. The purpose of this paper is to describe the micromorphological and mineralogical characteristics of these rocks. A large number of calcrete thin sections were analyzed using a petrographic microscope. This study was supplemented by microchemical staining, cathode luminescence examination and X-ray diffraction methods.  The diagnostic features identified are rhizoliths (rhizocretion, root cast and root petrifaction), alveolar textures, in situ Microcodium grains, peloids, coated grains and pedogenic voids. According to these micromorphological results the studied calcrete belongs to the group of beta calcretes. The biofabric of this calcrete reflects an extensive vegetation cover and a relatively high degree of biological activity. Micromorphology and mineralogical composition of the calcrete gravels (i.e. dominance of calcite, quartz, illite±muscovite and illite/smectite) suggest a semi-arid/subhumid climate during calcrete pedogenesis. Within the Eocene calcrete gravel two main cement types have been distinguished: a meteoric vadose cement (vadose silt) and a phreatic one (drusy ferroan calcite spar). Drusy sparite is the typical cement of near-surface diagenesis, and this, together with its ferroan nature, leads to the conclusion that the main site of cementation of the Eocene calcrete was the meteoric phreatic zone.

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# Miocene volcanism of the Cserhát Mts (N Hungary): Integrated volcano-tectonic, geochronologic and petrochemical study

Authors: Teréz Póka, Tibor Zelenka, Ian Seghedi, Zoltán Pécskay and Emő Márton

New K/Ar ages and paleomagnetic data connected with volcano-tectonic observations detected three intermediate (andesitic) and three acidic (dacitic-rhyolitic) magmatic phases. Cserhát magmatic activity occurred between 21-12 Ma. The timing of the initial and final acidic and intermediate phases may be connected with the Mátra volcano situated to the east. During the Badenian (15-14 Ma) the volcano-tectonic evolution was relatively independent in the Cserhát Mts. The third acidic and intermediate volcanic phases, which developed in the Lower Sarmatian, show similar features as the final phases of the Mátra volcano. Based on the major and trace element geochemistry the acidic rocks result from partial melting of the lower crust. Most of the intermediate volcanic rocks were generated from a rather homogeneous fluid-modified source (lithospheric), as triggered by an important heat transfer event. Initial melts sometimes experienced mixing or contamination in the lower or upper crust. This was a period of strong extensive tectonics. The rock of the second and third intermediate phases suggests minor fractional crystallization in the intermediary magma chamber(s).

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# Monazite Th-U-total Pb ages of "bostonite" and granite in the Mecsek and Velence Hills

Authors: György Pantó and Géza Nagy

The age determination method based on microprobe measurements of the Th, U and Pb contents of monazite, and used since the nineties, was applied to Hungarian igneous rocks: the so-called "bostonite" and the granitoids of the Velence Hills and Mecsek Mountains. Measurement results were evaluated by two different methods that produced similar ages; for the sake of precaution the obtained values were mostly accepted by the greater uncertainty domain calculated by linear regression. The age of 117±13 Ma for the "bostonite" proves that this rock is a member of the Lower Cretaceous igneous series. The age of 210±18 Ma obtained for the Nadap granite in the Velence Hills agrees with published data while that of 255±17 Ma obtained for the Kismórágy microgranite in the Mecsek Mountains is younger than previously known.

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# Multipath effects in wideband fluctuating HF channels

Authors: V. E. Gherm, N. N. Zernov and H. J. Strangeways

Three-moded random ionospheric HF channel of propagation has been investigated.  The description of the channel has been given in terms of the scattering function and the appropriate codes for numerical calculations allowed assessment of the relative contributions of different modes in the scattering of the full field have been developed. In particular, the effect of overlapping of these contributions in the scattering function has been studied in the domain of Doppler spread -- group delay time. The dependence of this effect on the bandwidth of the signal and the geometry of propagation was investigated.

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# Multiscale signal-to-noise thresholding

Authors: W. Freeden, V. Michel and M. Stenger

The basic idea behind selective multiscale reconstruction of functions from error- afiected data is outlined on the sphere. The selective reconstruction mechanism is based on the premise that multiscale approximation can be well-represented in terms of only a relatively small number of expansion coeficients at various resolution levels. An attempt is made within a tree algorithm (pyramid scheme) to remove the noise component from each scale coefilient usinga priori statistical information (provided by an error covariance kernel of a Gaussian, stationary stochastic model)

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# New chronological and malacological data from the Quaternary of the Sárrét area, Transdanubia, Hungary

Author: Pál Sümegi

Quaternary geology, Quaternary malacology, radiocarbon data, Holocene, Pleistocene, paleoecology, stratigraphy, Transdanubia, Hungary

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# New conception in the surpluserror-method:  It can be significantly advantageous if the set of surpluserrors consists of mirrored sample pairs

Author: F. Steiner

If the surpluserror-sets consist of mirrored sample-pairs and the c magnitude ratio of the artificial error and of the natural one (the latter is contained in the measured values) is great enough (c ?? 1), the effectivity of the surpluserror-method can increase (i.e., the errors of the modelparameter-values can be more radically decrease) compared with the “old-fashioned” application of the surpluserror-method in which fully independent artificial error-sets of little magnitude (say, c = 1) were used.

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# New method of calculating water balance for the Castle Hill, Buda

Author: Géza Hajnal

In the previous centuries, a lot of energy has been expended on obtaining scientific data for the Castle Hill, Buda, declared a World Heritage site; however, only few scientists have carried out any hydrological research on the Hill, and of these only the results of Kessler's studies survived in a systematized form. The present paper is the summary of results of hydrologic and hydrogeologic investigations by the author, and provides a water balance model for the entire Hill.

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# New results on magnetic spherules from Hungary

Author: György Don

Magnetic spherules from Pleistocene terrestrial sediments in southern Hungary were systematically collected and investigated. By means of chemical analysis, Fe, Fe(Mn), Fe(Ni) and glassy (silicate) spherules can be distinguished. Some of them have characteristic features suggesting an extraterrestrial origin: Ni-bearing crust, Ni-rich core and especially the platinum group nuggets with their unique chemical composition. They could have been formed by meteorite ablation process.

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# A note on auroras during the so-called Maunder-Minimum

Author: W. Schröder

Based on visual noctilucent cloud data, the effect of the autumn transition of winds in the mesosphere is investigated. Following the autumnal transition of the mesospheric winds no noctilucent clouds were observed. The higher temperature of the winter mesosphere can be physically explain the fact that no noctilucent clouds occur during winter of the Northern Hemisphere. Accordingly, noctilucent clouds only occur on the typical summer mesosphere related to the low temperature there and due to the stable condition of the then mesospheric region.

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# Note on the estimating the sun's radiation output during the maunder minimum and the problem of solar variability

Authors: W. Schröder and H.-J. Treder

The general problem of solar variability (including the solar constant and various minima) is discussed in detail. We have no theoretical arguments about the amplitudes of the solar cycle, today. A new point is the statement of White et al. (1992) on the temperature of solar-type non-cycling stars. The theorems of the creation and annihilation of vorticity and magnetical fields prove that these processes essentially have a thermodynamical component.

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# The number of hotspots in three-dimensional numerical models of mantle convection

Authors: A. Galsa and L. Cserepes

Thermal convection has been modelled in a 3D model box, in order to estimate the areal density of upwellings and compare it to the density of hotspots, assumed as surface imprints of the cylindrical upwellings of the mantle. The number of the hotspots of the Earth is 40 to 100. If this is translated to a nondimensional areal plume density, using the depth of the convecting layer as length unit, a value of 2-6 is obtained for whole-mantle convection, while this value is 0.04-0.10 for a separately convecting upper mantle. The nondimensional theoretical areal plume density has been found about 0.2-1.0 for reasonable numerical models of the mantle. The fact, that the theoretical value lies between the densities estimated for one- and two-layer mantle systems, supports the possibility of a mixed regime, where some of the plumes come from the base of the mantle, some others from the 660 km boundary.

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# Observations and results of GPR modelling of sinkholes in Upper Silesia (Poland)

Authors: J. Ziętek, J. Karczewski and S. Tomecka-Suchoń

Using a RAMAC-GPR with a 200 MHz antenna, we obtained radargrams in an old coal-mining district of Upper Silesia (Poland), where exploitation holes represent a danger of collapse for existing structures. Despite some drawbacks, GPR methods seem to be the best technique for mapping and monitoring these holes, which may reach the surface after some time. In the first part of this paper, we show actual field measurements for a typical case, and in the second part we present preliminary theoretical investigations. We construct 2D synthetic radargrams based on the information we obtained from available geological data and the interpretation of the real radargrams. Thus, we formulate suggestions on how to optimize the methodology of locating sinkholes by the GPR technique, and give some clues concerning the theoretical interpretation of GPR data in this particular case.

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# On F2 response to geomagnetic storm

Author: V. U. Chukwuma

The interaction of solar wind with earth's magnetic field leads to a number of modifications of the F region global structure. Furthermore, the absorption of solar wind energy has the same phase all over the globe throughout the year. All these imply that there could be simultaneity in UT in global response of some F2 parameters to geomagnetic storms. Presently, F2 region global structure response to geomagnetic storm was studied using foF2 data obtained during the very intense geomagnetic storm (Ap?196) of 13-15 March 1989 from a global network of stations. The ionosonde stations located are at Ouagadougou (12.4), Manila (14.7ºN), Chung-Li (25.0ºN), Kokubunji (35.7ºN), Akita (39.7ºN), Boulder (40.0ºN), Rome (41.8ºN), Ottawa (45.4ºN), Wakkanai (45.4ºN), and Slough (54.5ºN) and Churchill (58.8ºN). The present result obtained using derived ratios R(foF2) show that all the stations showed some high degree of simultaneity in the depletion of foF2 between 0000 and 1200 UT on 14 March.

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# On latitude dependence of geomagnetic strom after-effects in ionospheric absorption

Author: V. U. Chukwuma

HF absorption enhancements following major geomagnetic storms are analysed, using the superposed epoch method, to examine the geomagnetic latitude limit of the after-effect phenomenon. The absorption data were obtained from one double hop and two single hop A3 transmission paths with ionospheric points at Fgeomag = 3:54oN and ~6. 40oN (15. 40 MHz), Fgeomag ~ 9N (4. 87 MHz), and Fgeomag ~ 11oN (6. 09 MHz) respectively. Presently, the results have shown that enhancement in absorption following major storms could be traced to the low latitude of 3. 54oN.

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# On the relevance of convolution of uniform distributions to the theory of errors

Author: D. Monhor

In recent years the uniform distributions and their convolutions find such applications that are relevant to geodesy-more precisely-to the modern theory of errors: (i) The convolutions of uniform distributions have been applied to the error distribution arising from data processing; (ii) Within the framework of geodesy, outliers were assumed to be distributed with uniform distribution. Bearing in mind these new developments and integrating these isolated topics, in this paper new closed formulae for the probability density and distribution functions of the sum of independent uniform random variables with unequal supports are derived. A brief outline of the relevance of convolutions of uniform distributions to the theory of errors related to astronomy and geodesy is given in historical setting. Along with these, the origin of uniform distribution is discussed with special emphasis on the root of the theory of errors.

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# On the role of remote magmatic source and intrabasinal redeposition in the genesis of the Toarvian Úrkút Manganese ore, Hungary

Authors: Zoltán Lantos, István Vető, Mária Földvári and Péter Kovács-Pálffy
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# Paleogene igneous activity along the easternmost segment of the Periadriatic-Balaton Lineament

Author: Kálmán Benedek

In the Pannonian Basin three Paleogene igneous regions can be outlined, namely the Zala Basin Shear Zone, the Velence Mts and the Recsk Region. These igneous regions are aligned along the easternmost Periadriatic-Balaton Lineament System.  The igneous bodies are built up mostly by effusive rocks (andesite, dacite and basaltic andesite); however, intrusive rocks (tonalite, diorite) have been identified as well. The radiometric age of the effusive and intrusive rocks is scattered around 30 Ma, which falls into the range of the igneous bodies aligned along the Periadriatic Line (Bergell, Adamello, Riesenferner, Karawanke, etc.). Nevertheless, an Eocene onset of the magmatic activity in the Pannonian Basin is accepted on the basis of biostratigraphic data. As major and trace element composition range of the Paleogene igneous suites in the Pannonian Basin are basically the same, they are thought to have undergone the same pre-crystallization history. Geochemical characteristics of these calc-alkaline igneous rocks suggest that the magmatic activity represents a post-syncollisional volcanic arc environment.

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# Peculiar hydrothermal caves in Budapest, Hungary

Authors: Szabolcs Leél-őssy and Gergely Surányi

In the capital of Hungary, Budapest, which Ottokar Kadic`´ called 'the capital of the caves', beneath the Rózsadomb (Rose Hill) district of the city, many thermal-karstic caves were discovered based on the lucky coincidence of geologic-hydrologic-speleological fundamentals. At present more than a hundred caves and cave indications are known in this 5-6 km2 area. The hills are made up of Triassic and Eocene carbonate sequences. Five caves are km-size. The corridors are sometimes longer than 100 m, and their walls are often adorned by spherical niches. The total length of the caves exceeds 35 km at present. The galleries of these caves are situated in the Eocene Szépvölgy Limestone. Some galleries and most of the cave indications can be found in the Eocene Buda Marl. The lowest galleries of some caves extend into the Triassic carbonate sequences. Although many paleokarstic cavities and caverns exist in the area the age of the largest caves - according to the preliminary results of investigations still in progress - is some hundreds of thousands of years only, based on the radiometric age of the syngenetic minerals. The exceptional value of the caves are the more than dozen species of minerals (especially the variety and mass of carbonates and sulfates are surprising). Minerals precipitated from warm water, minerals of aerosol formation, as well as recent, still developing minerals of cold water origin can also be found. The caves can be regarded as the fossil source levels of the present-day thermal springs at the banks of the Danube. Their genesis is interpreted as a result of mixing corrosion along tectonic fractures at the level of karst water.

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# Péter Márton is 70 years old. Curriculum vitae

Authors: T. Lipovics, J. Verő and L. Szarka
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# Petrochemistry of Variscan granitoids of Central Europe: Correlation of Variscan granitoids of the Tisia and Pelsonia Terranes with granitoids of the Moldanubicum, Western Carpathian and Southern Alps. A review: Part I

Authors: György Buda, Friedrich Koller and Jaromir Ulrych

Three major groups (A-C) of Central European Variscan granitoids can be distinguished based on petrologic and chemical data: A. Low-K, high-Na, calc-alkaline, alkali-calcic, met/peraluminous, I- and S-type, trondhjemitic (slightly granodioritic)-suite, mostly magnesian granitoids formed at the early stage of continent-continent collision (353-356 Ma). These types of granitoids occur in the northern part of the Central Bohemian Plutons (CBP) in the Moldanubian Zone or in the Austroalpine Zone of the outer belt of the Western Carpathian Plutons (WCP). The granitoid melt source originated from partially melted oceanic and continental crusts due to compression. B. High-K, high-Mg, calc-alkaline, metaluminous, I-type, monzonitic-suite granitoids with lamprophyre-derived small, ultrapotassic, Mg-rich intrusions formed in the post-collision zone, where the melts originated from the partially melted, uplifted, LIL-rich mantle and continental crust, due to extension (334-354 Ma) after earlier compression. These intrusions can be found in the southern part of the CBP, the eastern part of Southern Bohemian Plutons (SBP) and northwestern part of the Tisia Terrain. Later on (314-303 Ma), as a result of interaction of melts originated from depleted mantle and partial melted lower crust, low-K, high-Na, calc-alkaline-type granitoids formed during extension, occurring in the inner part of the WCP. C. Peraluminous, S- or S/A-type granodioritic-suite, small intrusions with some K-subalkaline and alkaline characters, formed in post-orogenic or probably rifting settings at the main tectonic zones, e.g. the Periadriatic-Balaton Lineament (Velence Mts, Gemericum) during the Lower Permian (274±1.7 Ma). The most unstable part of the Variscan orogenic belt was where the high K, Mg-calc-alkaline granitoid and ultrapotassic intrusions occur (Massif Central, Vosges, Black Forest, the southern part of the CBP, the eastern part of the SBP and the northwestern part of the Tisia Terrain). They formed the innermost part of the Variscan Belt; only the Tisia Terrain occurs in allochthonous positions, which originated from the Moldanubian Zone and were completely separated from it since mid-Cretaceous times.

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# Physical and chemical features of red clays in Northern Hungary

Author: József Fekete

Hungarian red clays are the result of soil formation from previous geologic periods. They were spread over areas which were dry during the Tertiary Period and were not covered by sediments. The climate of the Quaternary Period eroded them, so that today they can only be found in areas where they were protected against degradation or where their thickness and resilience could withstand the forces of erosion. Thus, red clays are fossil or relic products of soil formation. Since both their water regime and nutrient supply differ from soils formed in the Holocene, their economic importance is far from negligible; vineyards, forests and arable cultivation can be found on these areas. Their influence may be seen in more extensive territories where they were washed away, settled and became mixed with other soils.

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# Physical and chemical features of red clays in Northern Hungary

Authors: Mária Földvári and Péter Kovács-Pálffy

In this paper, data on the mineralogical composition of samples and a summary of those results are given (through a more detailed analysis of measurement data by using instrumental phase analytical methods concerning the examined boreholes of the two areas) that allow for the characterization of the loess and red clay sequences. The aim of our study was to characterize and correlate rocks in both areas using instrumental tests performed on samples from borehole drilled in the Hegyhát and Üveghuta areas.

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# Possible planetary excitation of earthquakes

Authors: D. Martini, K. Mursula and A. Körmendi

Several recent studies show the possibility of an important connection between the Earth's rotational motion  and the number of earthquakes (Stavinschi and Souchay 2001, Shanker et al. 2001). We discuss the long-term periodic variations (30 years and 60 years) in these two geophysical processes, as well in solar activity and the Sun's celestial orbit. The similarities in such periodicities suggest that solar system dynamics may contribute to both solar and geophysical phenomena.

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# Post-Newtonian corrections in the dynamics in the Earth-Moon system and their impor-tance for the relativistic theories of gravitation

Authors: W. Schröder and H.-J. Treder

As an example of a historical case study, some aspects of the post-Newtonian corrections in the Earth-Moon dynamics are described and discussed.

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# Post-seismic viscoelastic deformation

Authors: L. L. A. Vermeersen, R. Riva and R. Sabadini

The 3D quasi-static displacements during and following an earthquake provide a wealth of information on the internal  structure and rheological properties of the Earth. If an earthquake occurs in a region that has shallow-viscosity zones inside the crust or at the top of the mantle (asthenosphere), then post-seismic displacements of the crust on the order of millimeters per year are possible. These can be detected by means of permanent GPS stations in the years following a faulting event. In this