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Budapest, Hungary

Szanyi G.,MTA CSFK GGI | Suranyi G.,Geophysical and Space Science Research Group | Leel-ossy S.,Eotvos Lorand University
Quaternary Geochronology | Year: 2012

Several thermal karstic caves are known in the Rózsadomb area of Budapest, Hungary. On a small, 5-6 km2 territory more than 50 km of cave passages were mapped and documented to host significant cave raft deposits. Cave rafts precipitate at the surface of karst water lakes, and are potential indicators of former karst water levels.Thirty-two samples of cave rafts collected from different elevations in Pál-völgy Cave and five from Szemlo{doubleacute}-hegy Cave were dated by U-series methods using single-collector ICP-MS. Nine samples were older than 450 ka, the upper limit of U-series age determination. Uplift of the area and the associated history of karst paleo-water levels was assessed using the age and present-day elevation above sea level of the cave rafts.A two-phase uplift history was revealed. A slow emergence of the area was succeeded by more rapid uplift. Its beginning varies from cave to cave, suggesting differential movements of 0.15-0.32 mm/y. © 2012 Elsevier B.V. Source

Szalai S.,MTA CSFK GGI | Szokoli K.,MTA CSFK GGI | Metwaly M.,King Saud University | Metwaly M.,National Research Institute of Astronomy and Geophysics NRIAG
Landslides | Year: 2014

A new method, the so-called pressure probe (Pre-P) method, has been developed for detecting and characterizing mechanically weak zones which may not be visible from the surface and which may occur, e.g. due to landslides. On a high bank at Dunaszekcső, Hungary, the fracture system of the loess landslide area was investigated by large resolution applying this method and proved that (1) cracks as small as 2- to 3-cm wide are detectable; (2) the fractures follow each other almost periodically; and (3) on the side of the fractures towards the slump, there are less fractured zones whose width correlates with the width of the given fracture. We also demonstrated that on the passive side of the clearly visible fracture, (1) there are also fractures along which future rock displacement is expected; (2) these fractures are at least as wide as the active side fractures; and (3) the blocks there are about twice as wide as those on the active side. A block several meters wide is expected to fall before the main mass movement. The Pre-P method seems to be the most powerful tool to map the fracture system of such landslides because of its speed, simplicity of application, cost and interpretation. The Pre-P profiles and maps of the fracture system of a landslide enable to understand landslide evolution and delineate endangered areas earlier than by other methods. © 2014, Springer-Verlag Berlin Heidelberg. Source

Szalai S.,Hungarian Academy of Sciences | Wesztergom V.,MTA CSFK GGI | Szokoli K.,MTA CSFK GGI | Frigy A.,University of West Hungary | Pracser E.,MTA CSFK GGI
8th Congress of the Balkan Geophysical Society, BGS 2015 | Year: 2015

Firstly a short introduction is given about the theory of the g11n configurations which belong to the group of the geoelectrical quasi null arrays. On the basis of our numerical investigations the application of these arrays seem to be rather perspective. Their field application is however difficult because of the complexity of the inversion of the data of these arrays. These arrays have very large geometric factor, they may change their sign and they can produce very sharp changes. Using an own developed code we inverted field data. The very first results show the field applicability of these configurations. Source

Szanyi G.,MTA CSFK GGI | Graczer Z.,MTA CSFK GGI | Gyori E.,MTA CSFK GGI
Acta Geodaetica et Geophysica | Year: 2014

On 22 April 2013 an earthquake of magnitude 4.8 occurred near the village of Tenk (Hungary), which was the strongest Hungarian earthquake in the past 28 years. This event was detected by a number of seismological stations, thus it is well documented. Nevertheless, it is still possible to get further data through macroseismic surveys, which cannot be obtained using seismological instruments, but are very useful for the understanding of seismic properties of the affected area. The studied earthquake was felt in approximately third of the territory of Hungary. The number of incoming macroseismic questionnaires was over eight hundred and damage descriptions for the epicentral area reached almost one thousand. Intensity evaluation was carried out following the European Macroseismic Scale guidelines. Intensities were assigned to 211 places, including 23 districts of Budapest. The earthquake caused non-structural building damages, the epicentral intensity was estimated as VI on the EMS-98 scale and was assigned to three villages: Tenk, Átány and Erdotelek. The event was widely felt west to the epicentre, but much less observed in the east direction. The asymmetry of the intensity distribution raises questions and requires further investigation. © 2014 Akadémiai Kiadó. Source

Szanyi G.,MTA CSFK GGI | Graczer Z.,MTA CSFK GGI | Gyori E.,MTA CSFK GGI
Acta Geodaetica et Geophysica | Year: 2013

We studied the Rayleigh wave group velocities beneath Hungary using ambient seismic noise tomography. Noise data were gathered from 17 broadband seismological stations in and around the Pannonian basin. The cross-correlation method was used to calculate the Green's functions. Group velocities belonging to the fundamental mode Rayleigh waves were determined by multiple filter technique. We measured the dispersion curves for each station pair in a period range of 7-28 s and computed maps of group velocity distribution using a 2D tomography method. The group velocity maps of 7-14 s periods correlate well with sedimentary thickness and regional geology. Velocity anomalies observed at longer periods reflect the effect of the crustal and mantle structural features. © 2013 Akadémiai Kiadó, Budapest, Hungary. Source

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