Integrated evaluation of urban groundwater hydrogeochemistry in context of fractal behaviour of groundwater level fluctuations

The present study was carried out as part of a complex survey of urban groundwater quality and quantity in Szeged, southeast Hungary. The concentrations of 12 inorganic contaminants in 28 shallow groundwater monitoring wells were determined over a 2-year period (2010–2012). The evaluation of concentrations indicates remarkable contamination all over the city. Discriminant analysis (DA) was used to evaluate the spatial changes of groundwater quality. The groundwater levels were measured over a 14-year period (2000–2013). The fractal properties of water level fluctuations time series characterizing the groundwater system and Tisza River were investigated using rescaled range (R/S) analysis. The resulting Hurst exponents clearly showed the persistency and thus long memory effects of both the groundwater and the river flow. Comparison of the results of DA with the results of R/S analysis thus implies that the geological conditions and the changing groundwater quantities are not related to groundwater quality.

EDITOR A. Castellarin

ASSOCIATE EDITOR A. Fiori     

Geoelectric Characterization of Thermal Water Aquifers Using 2.5D Inversion of VES Measurements

This paper presents a short theoretical summary of the series expansion-based 2.5D combined geoelectric weighted inversion (CGWI) method and highlights the advantageous way with which the number of unknowns can be decreased due to the simultaneous characteristic of this inversion. 2.5D CGWI is an approximate inversion method for the determination of 3D structures, which uses the joint 2D forward modeling of dip and strike direction data. In the inversion procedure, the Steiner’s most frequent value method is applied to the automatic separation of dip and strike direction data and outliers. The workflow of inversion and its practical application are presented in the study. For conventional vertical electrical sounding (VES) measurements, this method can determine the parameters of complex structures more accurately than the single inversion method. Field data show that the 2.5D CGWI which was developed can determine the optimal location for drilling an exploratory thermal water prospecting well. The novelty of this research is that the measured VES data in dip and strike direction are jointly inverted by the 2.5D CGWI method.     

The “Cross Doppler count” method for comparison of Doppler receiver performances

A fast and simple method is proposed for Doppler receiver pair quality evaluation. By evaluating collocated raw Doppler data the noise characteristics of the receivers can be directly obtained. Test evaluations of JMR receivers are presented.     

Geokinematics of Central Europe: New insights from the CERGOP-2/Environment Project

The Central European Geodynamics Project CERGOP-2, funded by the European Union from 2003 to 2006 under the 5th Framework Programme, benefited from repeated measurements of the coordinates of epoch and permanent GPS stations of the Central European GPS Reference Network (CEGRN), starting in 1994. Here we report on the results of the systematic processing of available data up to 2005. The analysis has yielded velocities for some 60 sites, covering a variety of Central European tectonic provinces, from the Adria Indenter to the Tauern Window, the Dinarides, the Pannonian Basin, the Vrancea Seismic Zone and the Carpathian Mountains. The estimated velocities define kinematical patterns which outline, with varying spatial resolution depending on the station density and history, the present-day surface kinematics in Central Europe. Horizontal velocities are analyzed after removal from the ITRF2000 estimated velocities of a rigid rotation accounting for the mean motion of Europe: a 2.3 mm/year north–south oriented convergence rate between Adria and the Southern Alps that can be considered to be the present-day velocity of the Adria Indenter relative to the European Foreland. An eastward extrusion zone initiates at the Tauern Window. The lateral eastward flow towards the Pannonian Basin exhibits a gentle gradient from 1 to 1.5 mm/year immediately east of the Tauern Window to zero in the Pannonian Basin. This kinematic continuity implies that the Pannonian plate fragment recently suggested by seismic data does not require a specific Eulerian pole. On the southeastern boundary of the Adria microplate, we report a velocity drop from 4 to 4.5 mm/year motion near Matera to 1 mm/year north of the Dinarides, in the southwestern part of the Pannonian Basin. A positive velocity gradient as one moves south from West Ukraine across Rumania and Bulgaria is estimated to be 2 mm/year on a scale of 600–800 km, as if the crust were dragged by the counterclockwise rotation along the North Anatolian Fault Zone. This regime apparently does not interfere with the Vrancea Seismic Zone: earthquakes there are sufficiently deep (>100 km) that the brittle deformation at depth can be considered as decoupled from the creep at the surface. We conclude that models of the Quaternary tectonics of Central and Eastern Europe should not neglect the long wavelength, nearly aseismic deformation affecting the upper crust in the Romanian and Bulgarian regions.     

Surface kinematics in the Alpine–Carpathian–Dinaric and Balkan region inferred from a new multi-network GPS combination solution

The understanding of the intraplate tectonics of Central Europe requires a detailed picture of how stress is transferred from the interaction of the Eurasian, Nubian and Anatolian plates to the Alpine, Carpathian, Pannonian and Dinaric regions. Recent strain distribution is controlled by the Adria horizontal push, by the Vrancea vertical slab pull and associated horizontal displacements, and by the Aegean/Anatolia extension and slab-roll back. We present a horizontal velocity field for the Alpine-Carpathian-Pannonic-Dinaric and Balkan regions resulting from a new combination of seven different GPS networks formed from permanent and campaign stations. Dedicated velocity profiles in two specific regions are studied in detail. One is the Alpine Pannonian region, with a detailed picture of the NS indentation of the Adria microplate into the Southern Alps, in NE Italy, the deformation in the Tauern Window and the eastwards kinematics of a Pannonian plate fragment. The second study region includes Transylvania, the Southern Carpathians up to the Aegean sea and Albania, where a major right lateral shear deformation exists as a consequence of the NE convergence of the Apulia platform towards the Dinarids, and the SSW motion of Macedonia, Western Bulgaria and Rumania, related to the Hellenic arc dynamics in the Eastern Mediterranean. The profiles in the Alpine–Pannonian area indicate that a velocity drop of 2.5 +/− 0.4 mm/yr associated with the Adria indentation concentrates on a segment of some 50 km south of the Periadriatic fault. The deformation becomes extensional by a similar amount just north of the Periadriatic fault, in the Tauern Window, where the updoming of the Tauern Window implies vertical motion which could well be associated with surface extension. In the EW profile, we observe a sudden velocity change of 1.5 +/− 0.2 mm/yr in 20 km, corresponding to the right lateral Lavant fault, which seems to mark the border between dominant indentation kinematics to the West and dominant extrusion kinematics to the East.Three profiles are considered in Southern and Eastern Europe: one across the lower Adriatic sea from Apulia in Italy to the southern Dinarides, which enables it to constrain the velocity drop associated with the subduction of the Adria microplate into the Dinarides to 3.2 +/− 0.5 mm/yr in 140 km. The second profile is longitudinal and constrains the velocity inversion of 7.4 +/− 1.0 mm/yr in 350 km associated with right lateral shear faults in Albania. The third profile crosses the Transylvania region with a shortening of 2.3 +/− 1.0 mm/yr in 220 km, and the Wallachian–Moesian region up to the Chalcidic peninsula in N Greece. This lower part of the profile implies an extensional stretch of the upper crust of 3.2 +/− 0.9 mm/yr in 440 km, culminating in the Hellenic arc. Strain rate maps are presented in this regional scale, showing the excellent agreement between fault plane solutions of crustal earthquakes and the eigenvectors of the GPS derived two dimensional strain rate tensor.Three profiles are considered in the Balkan and SE Carpathians: one across the lower Adriatic sea from Apulia in Italy to the southern Dinarides, which enables to constrain the velocity drop associated to the subduction of the Adria microplate into the Dinarides to 3.2 +/− 0.5 mm/yr in 140 km. The second profile is longitudinal and constrains the velocity inversion of 7.4 +/− 1.0 mm/yr in 350 km associated to right lateral shear faults in Macedonia, a highly seismic region. The third profile crosses the Transylvania with a shortening2.3 +/− 1.0 mm/yr in 220 km, and the Wallachian–Moesian region up to the Chalcidic peninsula in N Greece. This lower part of the profile implies an extensional stretch of the upper crust of 3.2 +/− 0.9 mm/yr in 440 km, culminating in the Hellenic arc.     

Microalgal productivity, community composition, and pelagic food web dynamics in a subtropical, turbid salt marsh isolated from freshwater inflow

Carbon entering the food web originating from microalgal productivity may be as important to salt marsh consumers as carbon originating from vascular plant production. The objective of this study was to further our understanding of the role played by microalgae in salt marshes. We focused on microalgal productivity, community dynamics, and pelagic food web linkages. Across three consecutive springs (2001–2003), we sampled the upper Nueces Delta in southeast Texas, United States; a shallow, turbid system of ponds and elevated vegetated areas stressed by low freshwater inflow and salinities ranging from brackish (11) to hypersaline (300). Despite high turbidity and low external nutrient loadings, microalgal productivity was on the order of that reported for vascular plants. Primary productivity in surface waters ranged from 0 to 2.02 g C m⁻² d⁻¹ and was usually higher than primary productivity associated with the benthos, which ranged from 0 to 1.14 g C m⁻² d⁻¹. This was likely due to high amounts of wind-driven resuspended sediment limiting production at greater depths. Most of the water column microalgal biovolume seemed to originate from the benthos and was comprised mostly of pennate diatoms. But true phytoplankton taxa were also observed, which included cryptomonads, chlorophyhtes dinoflagellates, and cyanobacteria. Succession from r-selected to K-selected taxa with the progression of spring, a common phenomena in aquatic systems, was not observed. Codominance by both potentially edible and less edible taxa was found. This was likely due to decreased grazing pressure on r-selected taxa as salinity conditions became unfavorable for grazers. In addition to a decoupled food web, reduced primary and net productivity, community respiration, and microalgal and zooplankton population densities were all observed at extreme salinities. Our findings suggest that a more accurate paradigm of salt marsh functioning within the landscape must account for microalgal productivity as well as production by vascular plants. Because the value of microalgal productivity to higher trophic levels is taxa specific, the factors that govern microalgal community structure and dynamics must also be accounted for. In the case for the Nueces Delta, these factors included wind mixing and increasing salinities.     

VLBA multi-frequency monitoring of SS433

We present results of VLBA observations of SS433 at two epochs at 5, 8.4, and 15 GHz. The AU-scale region of the source is resolved and shows the familiar quasi-symmetric core-jet structures. But at another epoch, the maps show bright knots ejected a few days before the observation, while the core-complex disappeared. The bright jet components are completely depolarised with fractional polarization less than 0.5%. We also present the first VLBI image of SS433 at 22 GHz.     

Realization of the Hungarian geodynamic GPS reference network

The Pannonian Basin, which includes Hungary, tectonically belongs to the Eurasian Plate and is considered to be relatively quiet. Detailed geological studies revealed four main tectonic units in this area—the Tisza, Pelso, Austro-Alpine and Vepor units. All of these can be genetically related to tectonic processes in the Mediterranean and Alpine-Adria region.In 1989 the Satellite Geodetic Observatory (SGO) in cooperation with several institutions has initiated the establishment of a geodynamic global positioning system (GPS) Reference Network (HGRN) for three-dimensional deformation studies in Hungary. The HGRN consists of 13 primary sites which were selected according to geological and geophysical considerations and satisfied international standards for tectonic studies with the GPS technique. Particular care was devoted to the point marks concerning mechanical stability and the repeatability of antenna set-ups at the HGRN sites, therefore a point mark and a mechanical adapter to mount the GPS antenna had been developed at the SGO for this purpose. This point mark has been used at all HGRN sites. A GPS Datum Point was also established for Hungary in 1990 at the Satellite Geodetic Observatory; here quasi continuous observations are foreseen. The Penc station has been accepted as a fiducial station of the International GPS Geodynamic Service (IGS).The zero epoch measurements were completed in fall 1991 and monitoring is planned every second year at least for the next 10 years.Preliminary processing of the data has been carried out in the SGO, Penc and at the Lustbühel Observatory at Graz, using the TRIMVEC PLUS and BERNESE V3.2 programs respectively     

Geophysical methods in drinkwater protection of near-surface reservoirs

Two case histories are presented in which near-surface water-bearing formations and their overburden are examined. This survey utilized a combination of traditional geoelectric methods (direct current resistivity and time domain induced polarization) and a special shallow-depth engineering geophysical sounding method. This latter method was developed in Hungary to investigate near-surface unconsolidated formations such as clay, silt, sand, gravel and other similarly “penetratable” formations.For a gravel terrace, in addition to the usual parameter maps (resistivity, thickness, polarizability), combined multiparametric characterization maps have been plotted. These maps illustrate the hydrogeologic value of the water-bearing formations and the protecting capacity of the overburden better than the conventional parameter maps.Surface measurement results together with filtration coefficient values show how an inexpensive geophysical survey can successfully be applied in estimating the dangerous or protected situation of near-surface reservoirs and how such a survey can be used for siting reservoirs. This work enabled the near-surface geological structure to be determined, hereby providing orientation for more expensive, highly detailed surveys.     

Space VLBI Geodesy: background of an experiment proposal

Space VLBI is a new observing technique which will be available in the second half of this decade by radio telescopes as interferometer elements in orbit. Besides the main astronomical interests, this new development has some very interesting potential applications in satellite dynamics, geodesy and geodynamical research which qualify space VLBI a potential new technique in space geodesy. A geodesy demostration experiment (GEDEX) is being proposed for the Japanese space VLBI satellite-VSOP, with the main objectives of reference frame interconnections and orbit accuracy improvement of the space radio telescope. The paper gives a review of the special characteristics of space VLBI and a general background of the GEDEX proposal.