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Kis K.,ELTE Geofizikai es Urtudomanyi Tanszek | Taylor P.T.,NASA | Wittmann G.,MOL Magyar Olaj es Gazipari Nyrt | Toronyi B.,FOMI Foldmeresi es Taverze kelesi Intezet | Puszta S.,MTA Geodeziai es Geofizikai Kutatointezet
Magyar Geofizika | Year: 2010

The Pannonian Basin is a deep intra-continental basin formed as part of the Alpine orogeny. In order to study the nature of the crustal basement we used the long-wavelength magnetic anomalies acquired by the CHAMP. Some 165522 data distributed in a spherical shell were available, which were recorded between January 1 and December 31 of 2008. They covered the Pannonian Basin and its vicinity. Those magnetic data were interpolated into a spherical grid of 0.5° × 0.5°, at the elevation of 324 km by the Gaussian weight function. The vertical gradient of the total magnetic anomalies were also computed and mapped on the surface of a sphere at 324 km elevation. The former spherical anomaly data at 425 km altitude were downward continued to 324 km. To interpret those data we used an inversion method based on a polygonal prism model. The minimum problem was solved numerically by the simplex and simulated annealing methods. To solve the problem L1 norm was used in the case of Gaussian distribution parameters and L1 norm in the case of Laplace distribution parameters. We suppose that the magnetic anomaly is produced by the exsolution of hemo-ilmenite minerals in metamorphic rocks of the upper crust. © 2010 Magyar Geofizikusok Egyesülete.

Bada G.,ELTE Geofizikai es Urtudomanyi Tanszek | Szafian P.,ELTE Geofizikai es Urtudomanyi Tanszek | Vincze O.,Mol Nyrt | Toth T.,Geomega Kft | And 3 more authors.
Foldtani Kozlony | Year: 2010

High-resolution reflection seismic data acquired from Lake Balaton (mainly east of the Tihany Peninsula), provide a solid basis for a detailed analysis of the neotectonic habitat in the region. Two types of seismic profiling - imaging the subsurface with different resolutions and penetration - were utilised to carry out a structural investigation. Singlechannel seismic sections show the uppermost 20 to 30 metres with an unparalleled (decimetre scale) resolution. A closely-spaced seismic grid allowed a 3D structural interpretation to be performed, as well a lateral correlation of the tectonic features. Multi-channel seismic data have a lower (i.e. on the metre scale) resolution which is compensated by deeper penetration down to 150-200 m. The joint interpretation of the two data sets enabled (1) the kinematic interpretation and detailed mapping of neotectonic structural elements, (2) the analysis of the relationship between older (Miocene) and younger (neotectonic) structures, and (3) the reactivation potential of the reconstructed faults. Several shear zones were identified under Balaton; these were oriented mainly parallel to the lake axis. Areas of localised deformation contain numerous smaller scale faults arranged primarily in an en-echelon manner. Geometric and kinematic considerations suggest the presence of relatively wide, sinistral strike-slip fault zones, with most first-order faults being rooted in the basement. Their repeated reactivation is demonstrated in the Miocene as well as post-Miocene (neotectonic). Tectonic activity at the Berhida seismic zone east of Lake Balaton suggests that some of these faults could still be active. Besides faulting, gentle folding of the Upper Miocene (Pannonian s.l.) sediments is also notable. 3D mapping of key horizons and unconformities within the Pannonian strata allowed the identification of a well-defined system of anticlines and synclines of neotectonic origin. However, interpretation of fold axis distribution is not straightforward because features of a secondary deformation appear near the strike-slip fault zones; this has resulted in a complex, often en-echelon folding geometry. The neotectonic habitat at Lake Balaton was put in a more regional context by integrating the reconstructed structural pattern into a neotectonic model of South Transdanubia. Special attention was paid to the age of deformation, and the kinematics and morphological expression of fault geometries; this also referred to the present-day stress field and, particularly, the recent geodynamics of the Pannonian Basin System.

Toth Z.,University of Bremen | Toth T.,Geomega Kft | Szafian P.,TXM Olaj es Gazkutato Kft. | Horvath A.,TXM Olaj es Gazkutato Kft. | And 6 more authors.
Foldtani Kozlony | Year: 2010

The research efforts that took place after the outstanding Balaton project (1891-1918) of Lajos LÓCZY never led to any consensus on the origin and evolution of the lake. However, the application of modern palaeontological and geochemical methods in the framework of the Balaton investigations of the Hungarian Geological Institute (1981-2004) have settled a few critical issues and the first seismic survey of the lake was also performed in 1987. In the period of 1993 to 2007 the Geophysical Department of the Eötvös Loránd University (Budapest) regularly carried out seismic profiling on the lake in association with the summer fieldwork of the university's students. In 1993 Italian and in 2005 German experts took part in the surveys using their marine seismic acquisition technology. The most frequently applied instrument during the university research programmes has been a special Canadian device (IKB-Seistec™). This can generate a seismic signal in the 1 to 10 kHz frequency range and thus offers shallow penetration (20-40 m) and ultra-high resolution (10-20 cm). After a summary of the main results of earlier research, this paper outlines the basic principles and techniques of the seismic method. Then a compilation of the applied instrumentation and data processing is given to assist in understanding the interpretation of the seismic sections of Lake Balaton in the following set of papers in this volume.

Toth A.,ELTE Geofizikai Es Urtudomanyi Tanszek | Havril T.,ELTE Altalanos Es Alkalmazott Foldtani Tanszek | Madlne S.J.,ELTE Altalanos Es Alkalmazott Foldtani Tanszek | Muller I.,ELTE Altalanos Es Alkalmazott Foldtani Tanszek
Magyar Geofizika | Year: 2012

The lakes of the Tihany Peninsula are located in maar structures which were formed by the phreatomagmatic volcanism of the region dating 7.96 Ma B.P. (Sacchi, Horváth 2002). Interaction between groundwater and the lakes has not previously been examined. In order to understand the complex hydrogeology of the Tihany Peninsula, geophysical radio-magnetotelluric (RMT) measurements were carried out to determine the electrical resistivity and geometry of shallow formations, and were coupled with hydrogeological observations. Maar lake sediments, maar structure filling pyroclastic deposits and tephra ring formations were able to be distinguished according to the resulting resistivity values. Electrical resistivity values were converted to hydraulic conductivity for each formation. The results of the study improved to clarify the hydrostratigraphic conditions of the area and hydrologic knowledge of the peninsula, and could also be applied to other maar regions.

Telbisz T.,ELTE Termeszetfoldrajzi Tanszek | Kovacs G.,ELTE Termeszetfoldrajzi Tanszek | SzeKely B.,ELTE Geofizikai es Urtudomanyi Tanszek | Karatson D.,ELTE Termeszetfoldrajzi Tanszek
Foldtani Kozlony | Year: 2012

Classical single-line elevation profiles often comprise some arbitrariness. Swath profiles can overcome this problem since the elevation values are considered not only along a line but along a swath. In a swath profile, the pixels are classified according to distance and statistical parameters (min, mean, max) of the classes are plotted against distance. The swath is usually a rectangular form but more irregular planforms are also possible. A special case is the "central swath", in which distance is calculated from a centre point. Besides some methodological development, this paper presents three case studies. In the first example, swath analysis is used to characterize the tilted surfaces found in the hilly landscape between the Ko{double acute}szeg Mts and the Rába river (in W Hungary and E Austria). Swath analysis also works for the more dissected western sections, thus proving the strength of this method. The second example discusses the Torockó (Trascǎu) Mts (in the eastern part of Apuseni Mts in Romania). Here, some water gaps and several wind gaps cross the karstic main ridge. Swath analysis helped to identify wind gaps not mentioned in previous publications and therefore it supports important data when outlining the drainage evolution of the area. Third, "central swath" profiles were used in order to numerically characterize the denudation of Central Andean volcanoes. The "ideal volcanic cone profile" is derived from the Parinacota volcano and this model enables comparisons to be made with older, more denuded volcanoes in order to quantify erosion volume.

Timar G.,ELTE Geofizikai es Urtudomanyi Tanszek | Csillag G.,Magyar Allami Foldtani Intezet | Szekely B.,ELTE Geofizikai es Urtudomanyi Tanszek | Szekely B.,Vienna University of Technology | And 4 more authors.
Foldtani Kozlony | Year: 2010

The quality and resolution of digital elevations models (DEMs) are rapidly improving and the analyses they provide are sutiable tools for reconstructions. This study considers a reconstruction of the former inundation levels which characterize the maximum extent of lakes using DEMs and it focuses on Lake Balaton. However, the static filling algorithms which model the inundation in a DEM by a pre-set level often do not produce reliable results. To achieve more reliable models it is suggested that it is necessary to take into account the results of repeated and precise levellings as well. According to these results, the northern shore and foreland of Lake Balaton is being uplifted, in contrast to the southern one. The rate of this relative movement is a few tenths of a millimetre per year. Assuming the rate of uplift has been constant over the past few millennia, in the Early and Middle Holocene the level of the northern embayments (especially the one far to the north at Tapolca) were lower by 2-3 metres compared to the southern ones (especially the one far to the south at Nagyberek). Using this method (DEMs with repeated levellings) more reliable results can be obtained; this approach results in an outline of the lake which fits well to the lacustrine sediments mapped by LÓCZY. Furthermore, there is still no overflow on the southern edge of the watershed. The small differences between this outline and the extent of mapped lacustrine sediments, however, may reflect the small temporal variations of the vertical movements over the recent millennia.

The Hilbert transform is a general procedure, it can be an effective tool in the interpretation of local magnetic measurements. Magnetic measurements presented in this paper were done with the aim of recultivation of the Kiskunhalas local waste yard. The task was to separate the different places where different amount of iron containing objects had been deposited. From the Hilbert transform of the measured data, an envelop of an analytical function was obtained. After a proper low-pass filtering, the envelope function indicated the locations, where higher amount of iron had been deposited. © 2013 Magyar Geofizikusok Egyesülete.

Lichtenberger J.,ELTE Geofizikai Es Urtudomanyi Tanszek | Ferencz Cs.,ELTE Geofizikai Es Urtudomanyi Tanszek
Magyar Geofizika | Year: 2012

The inner magnetosphere is the area where the physical processes driven by the energetic particles originated from the Sun interact with the waves propagated there in the wave-particle interaction. This phenomenon is called space weather and it plays an important role in the security of space assets. This is why these investigations are in front of research and supported by both EU FP7 and ESA SSA programs. Space Research Group of Eötvös University is involved in these investigations by ground based and satellite measurements.

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