This paper presents the results of percentage occurrence of night time VHF ionospheric scintillations characteristics of radio beacon signals of 244/250 MHz transmitted from Fleet Satellite (positioned at 73°E Longitude) received over Udaipur (24.6°N, 73.7°E, Dip angle 35°) during different epochs of solar activity periods from March 1986 to April 2000. The long term observations of VHF scintillation phenomenon, spanning a solar cycle (1986 to 2000) which covers low, mid as well as high solar activity period, has shown the consistent nocturnal temporal hourly, seasonal and solar cycle variations in scintillation occurrences. The night time VHF radio wave scintillations has been found to be at maximum percentage occurrence during the equinoxes months and less during winter and the least during summer months in all the epochs of solar activity period. The monthly variations of percentage occurrences of VHF ionospheric scintillation activities are seen to be increased during high solar activity years and also showed that highest values of percentage of occurrences in equinoctials months during high solar activity years. The prominent feature of discrete patchy nature of night time VHF amplitude scintillations specifically, over Equatorial Appleton anomaly region, is also presented in the light of seasonal and solar activity dependence of scintillation occurrences and patches duration. The results of present observations are also compared with the earlier works of similar stations.
We investigate the long-term Earth’s crustal deformations in New Zealand induced by the polar motion over the period from 1962 to 2009 using a tidal theory of an elastic and oceanless Earth. The theoretical values of crustal deformations are compared for the Gutenberg-Bullen, Ocean-Mantle, Shield-Mantle, 1066A, and PREM models of the Earth. The horizontal and vertical deformations computed using these models differ less than 0.1 mm and 0.15 mm, respectively. The maximum horizontal motion in New Zealand is less than 4 mm over the period from 1962 to 2009. The maximum vertical motion is larger by a factor of about 3 (up to 12.2 mm). The variations in horizontal and vertical motions at different locations within New Zealand are bellow 1 and 3 mm, respectively.
Authors:József Deák, Sándor Kele, István Fórizs, Attila Demény and Gyula Scheuer
Linear correlation between the temperature and measured δ18Owater of Budapest thermal karst water system presents an opportunity to estimate both the temperature and δ18O of the depositing water if only the δ18Otravertine is known.
Our observations on several Hungarian groundwaters and travertines deposited recently from them resulted that δ18O data of travertines originating from cold karst water and thermal water of porous aquifer are close to the “experimental“ curve presented by Friedman and O'Neil (1977). Conversely, the calculated fractionation factors of thermal karst waters significantly deviate from the experimental curve following an “empirical-curve“ (R2 = 0.99) as: 1000*lnα = (2.76*106)/T2 − 1.31.
The empirical equations calculated by this “empirical-curve“ as Twater = (25 − δ18Otrav)/0.22 and δ18Owater = 0.186*δ18Otrav − 14.22 are usable only for the Budapest thermal karst regime and only for recent travertines. Extrapolation of these equations to the past and use them to estimate the deposition temperature of paleo-travertines needs detailed information of the paleoclimate and age of travertine.
Authors:Izabella Havancsák, József Fekete and Bernadett Bajnóczi
The paper presents an application of carbon isotope analysis in the archaeometric research of graphite-tempered ceramics. Graphite separated from Celtic graphitic ceramics were analysed from Szűr, Szajk and Dunaszentgyörgy archaeological sites from the South Transdanubian region of Hungary. Variation in δ13C values of graphite in the sampling sites is attributed to the characteristics of graphitic metamorphic rock used for tempering. The carbon isotope results will serve as basis for further provenance research on graphite.
Authors:István Fórizs, Sándor Kele, József Deák, Ali Gökgöz, Mehmet Özkul, Mehmet Oruç Baykara and Mehmet Cihat Alçiçek
The isotopic compositions of the Hungarian warm and cold water samples are spread in a wide range along the Global Meteoric Water Line (GMWL), which is a result of the significant change in the climate (mainly temperature) during infiltration (Last Glaciation and Holocene) and of the mixing process along the fault zone. The thermal karst water is isotopically lighter as it was infiltrated in a 7 to 9 °C cooler climate in the Ice Age. However, in the Denizli Basin isotopic composition of all of the thermal, lukewarm and cold waters varies in a relatively narrow range, with the exception of some warm waters whose d18O values have been shifted as a result of water-rock interaction.
Isotope data prove that all the waters in the Denizli Basin infiltrated in the Holocene under more or less the same climate, so these waters are young indicating much shorter transit time from the recharge to the discharge areas because of faster flow under the surface or shorter path of the subsurface flow.
Authors:Laurent Simon, Christophe Lécuyer, François Martineau and François Robert
Hydrogen gas is produced during the oxidation of the FeO component of silicates by water. This redox reaction occurs during the high-temperature (400 °C–800 °C) hydrothermal alteration of oceanic crustal rocks, and is responsible for H2 production at mid-ocean ridges. Samples of international reference biotite NBS30 (δD = −65.7‰) were reacted at high temperatures (600–1200 °C) in a high-vacuum line, releasing both structural water and hydrogen gas. An apparent fractionation factor α, derived from D/H measurements of water and hydrogen gas, is linearly dependent on T−2 following the equation α = 1.024 + 2477296.T−2 with a residual standard deviation σ = 0.023. The apparent D/H fractionation factors between water vapor and hydrogen gas during biotite oxidation show a dependency on T−2 that resembles those measured either by equilibration experiments or calculated from partition functions. Moreover, the apparent fractionation factors we measured are close to those determined at equilibrium in the same temperature range by Cerrai et al. (1954). This observation suggests that the D/H fractionation between H2O and H2 could be close to equilibrium during the reduction of water to hydrogen by the FeO component of silicates.
Authors:Jože Uhan, Sonja Lojen, Marina Pintar and Jože Pezdič
The chemical status of the shallow alluvial Savinja Valley groundwater body in Slovenia is poor, mainly due to the high concentration of nitrate in groundwater. This case study is therefore oriented in the assessment of groundwater vulnerability to nitrate pollution, as a base for the measure-planning processes. The article describes the use of isotope information of surface water and groundwater for the determination of possible sources of groundwater nitrate pollution. The isotope information of predominant soil and manure/septic waste nitrate origin, associated with other local physical and chemical boundary conditions and land use data, offers an interpretative support in the delineation of nitrate vulnerable zones.
Crude oil samples from uncommonly hot (>170°C) reservoirs of the SE-Pannonian Basin were studied for stable carbon and hydrogen isotope compositions of their different fractions. From two fields, 15 samples of different depths and temperatures were chosen for this study. The aim was to study the impact of extreme reservoir conditions on the isotope ratios of the different fractions and to find the ratios that show correlation with increasing depth and temperature.
We have shown that the behaviour of isotopes in these very hot oils differs from those from lower temperatures. The combined application of carbon and hydrogen isotope techniques is useful and may provide approximate information on reservoir conditions.
Authors:Attila Demény, Géza Nagy, Bernadett Bajnóczi, Tibor Németh, József Garai, Vadym Drozd and Ernst Hegner
In this study we report the first hydrogen isotope composition analyses on carbonado diamond along with cathodoluminescence and scanning electron microscopic imaging, electron microprobe analyses, and stable (H and C) and radiogenic (Sr) isotope measurements. The hydrogen of bulk carbonado (consisting diamond and pore-filling minerals) yielded ∼ −4‰, consistent with usual crustal or mantle-derived fluids. The diamond-related hydrogen component is about 70 ± 30 ppm and shows a D-depletion down to −200‰. Determined H isotope values — together with C isotope compositions — overlap the ranges for mantle-derived hydrocarbons. Textural characteristics and Sr isotope ratios of pore-filling florencite indicate that the carbonado was formed in a fluid-rich environment, underwent a significant high-temperature influence and finally suffered thorough alteration. Based on these observations, a terrestrial formation during interaction of mantle rocks/melts or subducted crustal materials and reduced C-H fluids seems to be more plausible than an extraterrestrial origin.
We describe a simple electrostatic model of hydrated ions [M(H2O)n]+ (n = 3–18, M = Li, Mg, Ca, K) which enables to calculate ion vibration frequency of the ground state. In this model the considered ion with a reduced mass vibrates in quasispherical well formed by the ion-dipole attractive potential and repulsive valence potential, these simplifications allowed to solve one dimensional Schrödinger equation, whilst the calculated ground state was considered as one of triply degenerated state of the three dimensional motion of the ion vs. hydration shell. The reduced partition function ratios were calculated from the vibration frequencies using Urey's (1947) harmonic approximation formula.
The results obtained in this way are in good agreement with those obtained by much more laborious ab initio molecular orbital methods, like SCF Hartree-Fock, DFT, MP2, etc. Moreover, we were able to extend calculations to hydrated Li and K ions surrounded with two shells of water molecules. These results are the first estimations of the upper limit of isotope fractionation in water solutions, which are 99.3‰ for Li and only 2.5‰ for K isotopes.
Authors:Attila Demény, Gabriella Schöll-Barna, Pál Sümegi, Péter Sipos and Brigitta Réka Balázs
In this paper we present sedimentological and geochemical data for a section of fluvial deposits from SE Hungary covering the period of 25 to 5 ky BP. Major and trace element geochemistry of bulk sediments as well as stable C and O isotope compositions of the carbonate content indicate significant changes in depositional facies and/or sediment provenance. Correlations of mineralogical and geochemical compositions were used to determine the stable isotope compositions of authigenic calcite component. Additionally, C and O isotope compositions of Unio crassus shell fragments were analysed that show a good agreement with climate change. Major climate change events within the studied time period were detected both in the shells and the authigenic calcite's compositions.
Authors:Nada Horvatinčić, Jadranka Barešić, Ines Krajcar Bronić, Bogomil Obelić, Krisztina Kármán and István Fórizs
Radioactive isotope tritium (3H) and stable isotopes of hydrogen (2H/1H) and oxygen (18O/16O) were measured during 2010 in the Sava River, precipitation and groundwater at 3 monitoring wells and 1 production well of the Petruševec aquifer, close to the Sava River in the Zagreb area. Significant increase of 3H activity in the Sava River was observed in June, (200 ± 20) TU, and in groundwater of all wells with damped response (maximum 60 TU) and with delay of 3–5 months related to the Sava River. This increase was explained by release of tritiated water from the Krško Nuclear Power Plant, 30 km upstream from Zagreb in the beginning of June 2010. Stable isotope analyses showed similar range of δ2H and δ18O values for the Sava River and groundwater samples with higher variations in surface water. Differences in monthly variations of δ18O values between particular monitoring wells, together with 3H values, indicated different infiltration times of surface water of the Sava River to different wells of the Petruševec aquifer.
Authors:András Galácz, Géza Császár, Barnabás Géczy and Zoltán Kovács
In the Jurassic rocks exposed in a small abandoned quarry on the northwestern edge of Nagy-Pisznice Hill in the Gerecse Mts, fairly well preserved parts of a crocodile skeleton was found in 1996. The bed which yielded the skeletal remains is the uppermost layer of the Kisgerecse Marl Formation exposed here and was determined as belonging to the Upper Toarcian Grammoceras thouarsense Zone. The beds of the sequence above and below were carefully sampled in the late 1990s, and the encountered ammonites were evaluated biostratigraphically. As a result, the Lower Toarcian Harpoceras serpentinum Zone, the Middle Toarcian Hildoceras bifrons and Merlaites gradatus Zones, and the Upper Toarcian Grammoceras thouarsense and Geczyceras speciosum Zones were identified. Within most of these zones the subzones and even the faunal horizons were successfully recognized. The lowermost beds above the underlying Pliensbachian red limestone did not yield any fossils; thus the lowermost Toarcian Dactylioceras tenuicostatum Zone could not be documented. The highest Toarcian ammonite zones also remained unidentified, because the beds of the Tölgyhát Limestone above were not sampled all the way up. This paper presents the lithostratigraphic and biostratigraphic details of the sequence, and the paleontological descriptions of the most important ammonites.
Authors:Péter Kiss, Katalin Gméling, Ferenc Molnár and Zoltán Pécskay
In the Tokaj Mts (NE Hungary), which is a part of the Inner Carpathian Volcanic Arc, large amounts of intermediate-acidic calc-alkaline volcanic rocks accumulated in a N-S oriented graben-like structure during the Badenian-Sarmatian-Pannonian period, in relation with the closure of the Alpine Tethys (Penninic) ocean. Although previous research on volcanism and related hydrothermal processes produced a huge number of K/Ar age data no systematic petrochemical database has been available up to now from the Tokaj Mts. In this study we publish new results of geochemical analyses completed on systematically collected basaltic, andesitic, dacitic and rhyolitic rocks, and of the spatialtemporal evaluation of petrochemical signatures, with special reference to origin of magmatism and relationships of rhyolite to hydrothermal mineralization. In the southern Tokaj Mts rhyolite contains K-feldspar phenocrysts, while this phenomenon is absent in the rhyolite from the northern areas of the mountains. In accordance with this, significant potassium enrichment occurs in the south (whole rock K2O content varies between 4.35 and 5.61 wt%), whereas rhyolite from the northern Tokaj Mts is less enriched in potassium (K2O content is from 3.28 to 5.1 wt%). The most significant difference between the northern and southern dacite is the age of their formation. They were formed at the same time as rhyolite and andesite (between 13.4 and 11 Ma) in the northern Tokaj Mts, while they are much younger (10.57–10.1 Ma) in the southern Tokaj Mts, where they post-date hydrothermal activity. The boron content (10.1–52.12 µg/g) and the patterns of other trace elements of the volcanic rocks show typical subduction-related features; however, direct influx of subduction-related fluids during magma generation can be excluded. A more plausible explanation for the magma genesis is decompression melting of a previously metasomatized mantle, enriched with subduction-related components. Additionally, the unmineralized northern rhyolite samples contain much less Cl (usually below 0.2 wt%) than the high-K rhyolite in the southern part of the Tokaj Mts (usually more than 0.2 wt%), which correlates with the presence/absence of spatially and temporally related epithermal mineralization in these areas.
Authors:Ildikó Buocz, Nikoletta Rozgonyi-Boissinot, Péter Görög and Ákos Török
This paper provides test results and interpretation of the shear strength of granitic rocks. The samples were obtained from Bátaapáti (South Hungary), where the low and medium-activity nuclear waste storage facility of Hungary is under construction. The experiments were carried out under laboratory conditions by using direct shear strength tests of samples drilled and cut from larger granitic blocks. The friction angles of both the maximal and residual shear stress, as well as the cohesion, were detected for various joint systems and also for the cut surface of the granitic rock. The interpretation of test results includes the evaluation of normal stress versus shear strength for cut, moderately rough, rough and calcite-filled joints. The tests have demonstrated that the average internal angle of friction for granitic rocks exceeds 20°, with a maximum of 39° for rough surfaces. Calcite-filled joints have lower friction angles, in the range of 16–23°. The peak shear strength of granitic test specimens was between 0.8 and 4.1 MPa, depending on the surface and joint fill.
Authors:Nada Miljević, Ana Pešić, Dušan Golobočanin, Zoran Gršić, Miroslava Unkašević and Ivana Tošić
Daily precipitation was collected in the period from May to December 2010, along with the corresponding meteorological data (air temperature, humidity, amount of precipitation) in the Vinca Institute of Nuclear Sciences (44°45′33″ N, 20°35′57″ E), Belgrade, Serbia. On the basis of backward trajectory analysis, three dominant trajectory categories are determined: southwestern Europe (SW), northeastern Europe (NE), and northwestern Europe (NW), which were associated with 49 (71%) of the events. The highest daily δ18O and δ2H values were measured on 9 December (−1.3‰ and −8.7‰, respectively), whereas the lowest values were measured on 28 December (−143.2‰ and −19.3‰, respectively). Circulation back trajectories, synoptic-scale surface and middle-tropospheric weather maps, and δ2H and δ2O values for 69 precipitation samples, were examined to determine the origin and direction of the air masses for each event.
Taxonomic and stratigraphic problems of the family Tmetoceratidae and the genera Dumortieria, Catulloceras, Cotteswoldia, Pleydellia and Tmetoceras included in it are briefly discussed. Fifteen species of Tmetoceratidae are described and illustrated from the Upper Toarcian-Aalenian ammonite assemblages of the Gerecse Mts (NE Transdanubian Range, Hungary). The fauna described here is closely allied to the Mediterranean Province of the Mediterranean-Caucasian Realm.
Geophysical data are specific physical responses of geological formations distributed over an area. These data are normally the physical parameters such as density, velocity, resistivity, susceptibility etc. of geological sources and hence bring a pattern of geological structures. It is conceived accordingly that this pattern recognition of such geophysical data will throw light on the spatial distribution and physical attributes of their geological sources. The well logging method considered as one of the geophysical method for the exploration of hydrocarbon, coal and base-metals, also has a strong role in finding the location and evaluation of geological resources.A novel approach known as Adaptive Neurofuzzy Inference System technique (ANFIS) is made to identify stratigraphy of Prydz Bay basin, east Antarctica. A geological stratum in terms of 1D model is made using datasets obtained from this area. The 1D model deduced as an ANFIS result is able to make geological sense of even additional thin sand sandwiched between clayey silt strata seams which unable to be resolved by other conventional methods. The analysed ANFIS results deduced to map horizons for hydrocarbon prospecting is verified with known coring datasets. These results are encouraging and provide stable and consistent solutions.
Measurements of Total Electron Content (TEC) were obtained from GPS and digisonde data, at Tucumán (26.69°S, 65.23°W), for days in different seasons, and with different geomagnetic activities, in 2004. Differences between both methods — associated with plasmaspheric content — are analyzed regarding hourly behavior, magnetic activity, and season; and are also compared with other latitude data. Results show a general good agreement between both methods, GPS measurements being generally higher around the diurnal maximum; results agree with theoretical predictions and findings from other authors as well.Maximum TECs occur in equinox, particularly, on magnetically perturbed days. Concerning the plasmaspheric content, our results do not show clear differences between quiet and perturbed days. The seasonal behavior can be associated with variations of the equatorial anomaly.
Geodetic measurements are commonly used for monitoring volcanic activities and crustal motions. Together with paleoseismic and other geologic observations, geodetic data are central in long-term forecast of earthquake hazards. Presence of outliers in geodetic data strongly affects least squares principle, which are extensively used for data analysis and modeling in geodesy. Thus, the positions of the geodetic points are computed as biased. Robust methods are techniques used to construct estimates describing well data majority. In this study, some robust methods and conventional tests for outliers have been tested on a number of linear and nonlinear geodetic adjustment models. The results are presented to illustrate the effectiveness of the methods. Furthermore, we discuss how the effectiveness of the methods changes depending on various key parameters for geodetic networks, i.e. the number of outliers, the magnitude of outliers, the degree of freedom, the number of observation and number of unknowns.
Authors:H. Chaudhuri, D. Ghose, R. Bhandari, P. Sen and B. Sinha
Helium was first observed in the sun and subsequently much later on the earth. Starting from the early days of its discovery, helium continues to be entwined with the Indian scientific scenario in more ways than one. The element thus has a special charm and significance to the currently emerging situation where it is applied to solve problems in the exceptionally challenging field of tracing the formation of earthquakes and anticipating its occurrence. The present article delves into some of the broader aspects of the problem through a historical approach. The paper also deals with the statistical analysis of the pre-seismic geochemical (He and 222Rn) anomalies recorded at our existing field site laboratories ahead of some major earthquakes that occurred in and around India. A description of the experimentally recorded geochemical (He, F−, Cl−, SO
, and B) and geophysical (temperature, pH, conductivity) characteristics of some thermal springs of north and north-east India is included. A dedicated mass spectrometer analyzed intensities of 3He and 4He in air sample made in our laboratory and implication of the pre-seismic enhancement of 3He/4He ratios measured in thermal spring gases is briefly discussed.
The Polar Regions are not covered by satellite gravity gradiometry data if the orbital inclination of the satellite is not equal to 90°. This paper investigates the feasibility of determining gravity anomaly (at sea level) by inversion of satellite gravity gradiometry data in these regions. Inversion of each element of tensor of gravitation as well as their joint inversion are investigated. Numerical studies show that gravity anomaly can be recovered with an error of 3 mGal in the north polar gap and 5 mGal in south polar gaps in the presence of 1 mE white noise in the satellite data. These errors can be reduced to 1 mGal and 3 mGal, respectively, by removing the regularization bias from the recovered gravity anomalies.
Authors:M. Obregón, M. Fernández-Fernández and G. Sáenz
This paper describes an unusual halo observed on the morning of 19 January 1787 from Caspe, Spain. The most striking characteristic of this phenomenon was a vertical tail of light that appears under one of the false suns.
The Mid-Hungarian Zone is a WSW-ENE trending composite structural unit in the basement of the Pannonian Basin that is made up of displaced crustal fragments (terranes) of South Alpine and Dinaridic origin. In the early stage of the Alpine evolution these fragments were located in various sectors of the NW Neotethys region, representing different paleogeographic settings from passive margin through continental slope to oceanic basement. Middle to Late Jurassic closure of the Neotethys led to the development of a suture zone made up of subduction-related complexes that can be followed all along the strike of the Dinarides. During the Cretaceous compressional stages, nappe stacks were formed from the accretionary complex and the fragments of the previously disrupted passive margin. Eastward extrusion (escape) of the ALCAPA Mega-unit during the Oligocene to Early Miocene led to large-scale displacement of fragments of this nappe stack, transporting them to their present-day position, and resulted in dispersal of the northwestern segment of the suture zone. The paper summarizes the basic characteristics of the dislocated blocks, evaluates their relationships and determines their original setting.
Authors:Gabriella Kiss, Ferenc Molnár, Sándor Kovács and Ladislav A. Palinkaš
The Darnó Unit in NE Hungary contains basalt and associated sediments related to the advanced rifting stage of Triassic age in the Neotethys. A detailed field study of five key outcrops and two deep wells revealed that only distal facies of basaltic lava flows of submarine volcanoes occur as blocks in the Jurassic mélange; the central and the most distal facies are missing. The advanced rifting-related Triassic and oceanic stage-related Jurassic basalt flows of the same mélange can be distinguished on the basis of lithostratigraphic, structural and textural features. The paper contains for the first time the detailed description of the key outcrops of peperitic facies consisting of a mixture of basalt and red micritic limestone. The occurrence of this facies is the principle key feature for discrimination in the field between Triassic and Jurassic basalt. In addition, four types of Triassic basalt were recognized: the Báj-patak-type, the Mély Valley-type, the Nagy-Rézoldal-type and the Reszél Hill-type. The observed peculiarities of advanced rift-related basalt are also compared to characteristics of volcanics encountered in wells drilled in the Darnó Unit. This comparison solves many problems of earlier interpretations of the studied wellbore sections.
The occurrence of the heteromorphic ammonoid Rhabdoceras suessi Hauer, 1860, is recorded for the first time in the Upper Triassic limestone of the Timon-Ciungi olistolith in the Rarău Syncline, Eastern Carpathians. A single specimen of Rhabdoceras suessi co-occurs with Monotis (Monotis) salinaria that constrains its occurrence here to the Upper Norian (Sevatian 1). It is the only known heteromorphic ammonoid in the Upper Triassic of the Romanian Carpathians. Rhabdoceras suessi is a cosmopolitan species widely recorded in low and mid-paleolatitude faunas. It ranges from the Late Norian to the Rhaetian and is suitable for high-resolution worldwide correlations only when it co-occurs with shorter-ranging choristoceratids, monotid bivalves, or the hydrozoan Heterastridium. Formerly considered as the index fossil for the Upper Norian (Sevatian) Suessi Zone, by the latest 1970s this species lost its key biochronologic status among Late Triassic ammonoids, and it generated a controversy in the 1980s concerning the status of the Rhaetian stage. New stratigraphic data from North America and Europe in the subsequent decades resulted in a revised ammonoid biostratigraphy for the uppermost Triassic, the Rhaetian being reinstalled as the topmost stage in the current standard timescale of the Triassic. The geographic distribution of Rhabdoceras is compiled from published worldwide records, and its paleobiogeography and paleoecology are discussed.
Authors:János Haas, Tamás Budai, Olga Piros, Péter Szeitz and Ágnes Görög
In the Pilis Range, NW of Budapest, contemporaneous Upper Triassic platform and basin facies occur. The paper presents the extent and basic characteristics of these facies with interpretation of their depositional conditions, and summarizes the available biostratigraphic data. Based on previous and recent studies a general depositional model is displayed and the history of the basin evolution is outlined. Within the Dachstein Platform an extensional intraplatform basin (Feketehegy Basin) came into existence during the middle part of the Norian. An asymmetric basin was formed, bounded by steep and gentle slopes, respectively. The platform progradation that may have resulted in the termination of the basin began at the gentle margin probably in the latest Norian-earliest Rhaetian.
Authors:Sándor Kovács, János Haas, Péter Ozsvárt, Ladislav A. Palinkaš, Gabriella Kiss, Ferenc Molnár, Sándor Józsa and Szilvia Kövér
The Mesozoic complex of Darnó Hill area in NE Hungary, according to well core documentation, is made up of two units. The upper unit, the Darnó Unit s.s., consists predominantly of blocks of ophiolitic rocks (pillow and massive basalt, gabbro) and subordinate abyssal sediments (red radiolarite and red pelagic mudstone of either Ladinian-Carnian or Bathonian-Callovian age, as well as bluish-grey, sometimes blackish siliceous shale of the latter age). The basalt is geochemically of MOR type, based on earlier evaluations. However, it comes in two types: reddish or greenish amygdaloidal pillow basalts with peperitic facies containing reddish micritic limestone inclusions, and green basalts without any sedimentary carbonate inclusion. The former type is probably Middle- Triassic, advanced rifting stage-related basalt, whereas the latter is probably of Jurassic age, corresponding to the Szarvaskõ-type basalt of the western Bükk Mountains. Pre-Miocene presence of an ultramafic sheet above the complex is indicated by serpentinite pebbles in the Lower Miocene Darnó Conglomerate.
The lower unit, corresponding to the Mónosbél Unit of the western Bükk Mountains, consists of lower slope and toe-of-slope type sediments: dark grey shale and bluish-grey siliceous shale of Jurassic age, both showing distal turbiditic character, with frequently interbedded carbonate turbidites and debris flow deposits containing cm- to dm-sized limestone and micaceous sandstone clasts. One to ten m-sized slide blocks of reddish, siliceous Triassic Bódvalenke-type limestone associated with the above-mentioned reddish, amygdaloidal basalt also occur. In one of the studied cores a block comprising evaporitic siliciclastics akin to those of the Middle Permian Szentlélek Formation and black, fossiliferous limestone similar to the Upper Permian Nagyvisnyó Limestone Formation of the Bükk Mountains, was also encountered.
A preliminary comparison with similar Triassic advanced rifting-type basalt and limestone/radiolarite of the western ophiolite zone of the Balkan Peninsula is presented (Fig. 1): the Zagorje region of NW Croatia, the Zlatibor-Zlatar Mountains of SW Serbia, and the North Pindos and Othrys Mountains, as well as Euboea Island, of Northern Greece. We propose the terms “Loggitsi Basalt” for such Triassic basalt containing peperitic facies, after the village of Loggitsion located in the central part of the Othrys Mts, and “Bódvalenke Limestone” for the transitional facies between Hallstatt Limestone and Triassic red radiolarite, after the village of Bódvalenke located in the Rudabánya Hills. The northwesternmost occurrence of both of these typical Neotethyan formations can be found in NE Hungary (Darnó Hill and Bódva Unit of Rudabánya Hills, respectively).
Authors:Sándor Kovács, György Buda, János Haas, Károly Brezsnyánszky and Szabolcs Harangi
The Mid-Hungarian (or Zagreb-Zemplin) Line of WSW-ENE strike divides the Pannonian basement into two mega-units, the Tisia Composite Terrane in the SE and the ALCAPA Composite Terrane in the NW. They became juxtaposed no earlier than the Middle Miocene (Karpathian). Their present adjacent zones show very different Variscan and Alpine evolution and relationships, which are briefly reviewed here and confronted in the light of detailed correlational work published during the last decade. The present contribution summarizes Variscan and Alpine evolution of units/terranes juxtaposed along the Mid-Hungarian Line, the major terrane boundary in the pre-Neogene basement of the Pannonian Basin, as can be seen on the Circum-Pannonian terrane maps.
The geologic key section at the northwestern margin of the village of Bódvalenke represents the stratotype of the Triassic Bódvalenke Limestone Formation and can be considered as the type section of the Bódva Unit of the Rudabánya Hills. The age of the exposed part of the formation in the type section ranges from the Late Anisian (Gondolella constricta cornuta partial range zone) to the early Late Carnian (Gondolella polygnathiformis interval zone). Its typical variety consists of purplish red to pinkish, strongly chertified, thinly-bedded micritic limestone, with frequent intercalations of mmthick purplish red shale layers and whitish-gray coquina beds. These beds are made up of tiny shells of Posydonia-like juvenile bivalves, often showing gradation. This deep water facies represents the transition between Hallstatt Limestone and red radiolarite. This facies type occurs from Oman via southern Turkey throughout the western ophiolite belt of the Hellenides-Dinarides until the Zagorje region in NW Croatia. Its northernmost, displaced occurrence is known in the Rudabánya Hills, NE Hungary, from where the type section is described and illustrated herein.
Authors:K. Gribovszki, F. Schulek-Tóth and P. Varga
Deterministic seismic hazard computations were performed along four different profiles across the downtown of Budapest. Synthetic seismograms were computed by the so called “hybrid technique”. By applying the hybrid technique it is possible to take into account the focal source, the path and the site effect together. Four independent computations have been performed using the same seismic source but different profiles. The parameters of the seismic source were adopted from the parameters of the well-known 1956 Dunaharaszti earthquake. The focal mechanism and the homogeneous and heterogeneous parts of the profiles are known from geophysical and geological data of the investigated area.As the results of the computations PGA (peak ground acceleration) grid maps of the downtown of Budapest for the three different components came into existence. Furthermore spectral acceleration (response spectra, SA) and RSR charts of the synthetic seismograms for the four different profiles were created. The PGA grid maps show that the maximal PGA values are situated at the eastern (Pest) part of the downtown, and their values are 50–200 cm/s
.For the downtown of Budapest a special seismic risk map have been prepared. This special seismic risk map were created on the basis of the difference between the maximal amplitude frequencies of SA of synthetic seismograms and the building’s eigenfrequencies at every 0.1 km
of the downtown. In order to determine the building’s eigenfrequencies microseismic noise measurement were performed at 6 different buildings in the downtown. The special seismic risk map shows that the buildings situated at the hilly western section of the downtown have higher seismic risk than the ones at the flat eastern part.
Many construction products contain asbestos. These are incorporated in the buildings in which we live. The term “asbestos” refers to six fibrous silicate materials that are naturally found in the Earth’s crust. It consists of many tiny fibers that can be seen only with a microscope. When products containing asbestos are disturbed, the asbestos fibers are broken into smaller pieces and these pieces float into the air even under the smallest air currents. Friable materials are therefore to be removed from buildings before demolition since they are considered hazardous waste, whereas non-friable materials may be normally treated as construction debris.Since asbestos represents material that is used in constructing floors, partition walls, thermal isolation, water and sewerage pipes, i.e., it represents part of the buildings, it is exposed to earthquake effect, as well.The present paper deals with the effect of earthquakes on asbestos plates and how this reflects the health of the population. Protection against these effects and regulations to be observed are also presented.
This study is related to the particular strong intermediate-depth Vrancea earthquakes. Its purpose is to confirm once again the significant influence of the seismic source mechanism to the seismic input at a given site through estimates of different engineering parameters, used to describe the damage potential of the ground motion due to an earthquake. Real and synthetic time-series have been used in the computations. The synthetic seismic wavelets have been computed applying the neo-deterministic seismic hazard assessment procedure and the relevant software and hardware facilities at the Department of Earth Sciences, University of Trieste, Italy. To derive the ground motion parameters of interest, all seismic signals have been uniformly processed by the
Authors:M. Bielik, Z. Alasonati-Tašárová, H. Zeyen, J. Dérerová, J. Afonso and K. Csicsay
Our paper presents the general overview of the current geophysical results, which helps to improve the geophysical image and the lithospheric structure of the Carpathian-Pannonian Basin region. Two different geophysical methods have been applied for the study of the structure and composition of the lithosphere as well as for determination of the lithospheric thermal structure. Firstly, integrated 2D modeling of gravity, geoid, topography and surface heat flow data was performed. Secondly, based on the results of the CELEBRATION 2000 seismic experiment, a large-scale 3D lithospheric gravity model was developed. The resulting map of the lithospheric thickness shows important variations in lithospheric thickness across the chain as well as along strike of the Carpathian arc. The sediment stripped gravity map is characterized by minima in the Eastern Alps and Western Carpathians. The maxima are observed in the Pannonian Back-arc Basin system, Bohemian Massif, Fore-Sudetic Monocline, Bruno-Silesian unit (BSU), Lublin Trough and partly in the Holy Cross Mts. and Malopolska unit. The Western Carpathian gravity minimum is a result of the interference of two main gravity effects. The first one comes from the lowdensity sediments of the Outer Western Carpathians and Carpathian Foredeep. The second one is due to the thick low-density upper and middle crust, reaching up to 25 km. The sediment stripped anomaly in the Pannonian Back-arc Basin system is characterized by gravity high that is a result of the gravity effect of the anomalously shallow Moho. The most dominant feature of the complete stripped gravity map is the abrupt change of the positive anomalies along the Pieniny Klippen Belt zone. The complete residual anomaly of the Pannonian Back-arc Basin system and the Western Carpathian orogen is characterized by a long-wavelength gravity low. The lowest values are associated with the thick low-density upper and middle crust of the Inner Western Carpathians. The European Platform is characterized by significantly denser crust with respect to the less dense crust of the microplates ALCAPA and Tisza-Dacia. That is why we suggest that the European platform represents consolidated, while the Carpathian-Pannonian Basin region un-consolidated crust.
Compilation of a homogenous earthquake catalogue, by expressing the size of the earthquakes in a unified magnitude scale, is an important tool for the seismic hazard evaluation. The most reliable and useful scale of magnitude to be chosen as the common measure of earthquake size, for both historically known and the instrumentally recorded events, is the moment magnitude,
. We investigate the empirical relationships between local magnitudes (
) calculated by the seismological agencies operating in the Western Balkan countries, and the relevant moment magnitude
, derived from the moment tensor analysis of medium-strong Western Balkan earthquakes. As result, regression relations converting
for these countries have been derived. Based on the proposed relations, an estimate of
which can be considered as a unified magnitude scale can be calculated for each earthquake of the regional catalogue.
The paper presents the results from the investigations of the effect of the local soil characteristics upon the seismic response at the surface of the Skopje city region. The SHAKE2000 computer program was used. Four soil profiles with a total thickness ranging between 7 m and 30 m were considered. The soil dynamic properties were defined by using data on the Skopje city region reported in literature. Horizontally, the soil layers were modeled as a one-dimensional soil column subjected to horizontal earthquake motion at the base. The seismic motions were defined using sets of four synthetic accelerograms compatible with the uniform hazard spectra at bedrock for return periods of 95, 475 and 1000 years. The results represent transfer functions as a representative measure of amplitude-frequency modification of local soils and absolute acceleration response spectrum at the free surface. The amplification factor was computed as a ratio between the acceleration spectra at the free surface and those at bedrock.
Recently, significant efforts were attempted to the re-organization of the former network established in the early 80’s. As a result, sixteen digital accelerograph stations were installed most of them concentrated in seismic active, densely populated and industrialized areas. In fact, analog SMA-1 recorders were replaced by digital QDR-s upgrading thus network’s effectiveness. A number of accelerograms from small magnitude events have been recorded and data were properly processed in order to obtain the maximum ground motion parameters. Particular importance was devoted to the “band-pass” filter parameters in order to eliminate the noise that influences the spectral characteristics of the signal as well as the absolute values of maximum ground motion parameters in case of strong earthquakes.
Authors:I. Paskaleva, S. Nikolova, L. Dimitrova and G. Georgieva
This work focuses on the assessment of seismic risk and the need of long-term studies on the territory of the only terrestrial Bulgarian salt deposit (Provadia, NE Bulgaria, 27.43E, 43.2N) in connection with the observed higher seismic activity and probable manifestations of technogenic seismicity in the region.The necessity of regular monitoring of the geodynamic situation, surface subsidences and control of the mining excavations are discussed. A review of the manifestations of some observed problems due to the long-term mining is done. Some results of the performed monitoring at the site during the 1989–2009 are provided. Results of the analyses of the geological and seismotectonic situation, assessment of the stress-strain state of the salt diapir, surface subsidence, analysis of the recorded accelerograms, analyses of the seismic regime variation are discussed. The use of these analyses and their possible applications for the general stability assessment of the cavern-pillar system is formulated.
Authors:C. Neagoe, M. Popa, M. Diaconescu and M. Radulian
The Vrancea seismic region represents a unique case of well-defined and intense intermediate-depth earthquake activity as a consequence of specific geodynamic processes at the continental contact between East-European, Moesian and Intra-Alpine plates. Apart the subcrustal earthquakes generated in the Vrancea slab, the analysis of seismicity puts into evidence two other clusters of subcrustal earthquakes (
> 50 km) toward the back-arc side of the SE Carpathians bend, one to the west (Sinaia), the other to the north-west (Braşov Depression) relative to the Vrancea seismic source. The hypocenters lay down between 50 to 105 km in Sinaia and between 50 and 136 km in Braşov Depression. The rate of seismic energy release is much lower (
≤ 3.7 in Sinaia and
≤ 3.1 in Braşov Depression) than for Vrancea activity. The seismicity pattern in the SE Carpathians back-arc region upper mantle correlates well with the high-velocity structures depicted by seismic tomography investigations suggesting possible remnant deep lithospheric roots apart from the narrow well-defined slab generating Vrancea major earthquakes. The results outline significant lateral heterogeneities in the mantle and provide new data for incorporating seismological, geotectonic and volcanological data in a unified modeling of the complex processes taking place in the study region.
The paper presents information on the seismic observation network of Belarus and describes in detail the development of instrumental observations in the region. The seismicity of the territory of Belarus has been thoroughly studied in recent years. The data available on earthquakes in the Belarussian territory were refined from literature and archive evidences, historical earthquakes near Mogilev were revealed. The Catalogue includes the results of continuous instrumental observations for 1965–2009 described in bulletins of seismic stations. An analysis of the location of earthquake epicenters suggests their uneven distribution over the area. Epicenters of low-magnitude earthquakes are abundant in the southern regions of Belarus and are confined to a zone of junction of the Pripyat Trough northwestern part and the Belarussian Anteclise. The induced seismicity of the Soligorsk mining region has been investigated. The investigation involved an analysis of dynamics of the annual space and time migration of epicenter grouping zones, which depends on the pattern of the induced changes of the present crust dynamic stress field. Seismic events are mainly confined to recent active fault zones.
There are numerous methods to modify Stokes’ formula with the usually common feature of reducing the truncation error committed by the lack of gravity data in the far-zone, resulting in an integral formula over the near-zone combined with an Earth Gravity Model that mainly contributes with the long-wavelength information. Here we study the reverse problem, namely to estimate the geoid height with data missing in a cap around the computation point but available in the far-zone outside the cap. Secondly, we study also the problem with gravity data available only in a spherical ring around the computation point. In both cases the modified Stokes formulas are derived using Molodensky and least squares types of solutions. The numerical studies show that the Molodensky type of modification is useless, while the latter method efficiently depresses the various errors contributing to the geoid error. The least squares methods can be used for estimating geoid heights in regions with gravity data gaps, such as in Polar Regions, over great lakes and in some developing countries with lacking gravity data.
Authors:H. Paudyal, D. Shanker, H. Singh, A. Panthi, A. Kumar and V. Singh
The study of seismic activity at some stage in 1963 to 2006 in the Western Nepal Himalaya and its adjoining regions (28–31°N and 79–82.3°E), reveal that seismicity is non-uniform in space and time. The analyses of fault-plane solutions of twenty-four earthquakes inferred that the Western part of Nepal Himalayan frontal arc is in compressed state in which seismic activity is dominated by thrust faulting. Based on orientation of P-axes, compressive stress directed north-south to northeast-southwest approximately perpendicular to the prevailing stress along the major trend of the Himalaya. Thrust faulting coupled with shallow dip of nodal planes reflects that the Indian continental lithosphere is under-thrusting at a shallow angle. This information suggests crustal shortening in north-south direction in which earthquakes are generated due to northward compression. In the adjoining Tibet parts earthquake activity is due to normal faulting with east-west extension. These might be due to the presence of a relatively strong Main Himalayan Thrust, the plate boundary fault below the Himalayas, would have favored the occurrence of thrusting. While, a weak Main Himalayan Thrust below Tibet along with initiation of the Main Central Thrust can explain South Tibetan Detachment (geodynamic process) and associated stress field in Western Nepal Himalaya and its adjoining regions.
Authors:G. Hassib, H. Hamed, S. Dahy, A. Hassoup and S. Moustafa
The spatial and temporal distribution of seismicity around the northern part of Lake Nasser in Aswan has been continuously monitored by a short-period seismograph network since 1982. Data of this network, which consists of 13 field stations distributed around the Kalabsha fault, has demonstrated occurrences of three swarm sequences during the past 26 years. The first swarm occurred in June 1987 on a fault segment about 8 km in length beneath the lake water. The largest magnitude of this swarm was 3.7. Its hypocenters were located within the shallow depth’s interval (i.e., 2 to 5 km from the ground surface). The estimated b-value for this swarm was 0.63. The second swarm sequence took place at the intersection of the Seiyal fault with Kurkur fault about 10 km to the north of the June 1987 sequence. This swarm occurred during the period from August to December 2004 with largest magnitude of 4.1. The focal depths of this swarm also ranged from 2 to 5 km. The
-value of this swarm was found to be 0.69. The third swarm occurred recently in April 2007 with largest magnitude of 4.2 at the same location of 1987 sequence but its focal depths ranged from 6 to 8 km and has the
-value of 0.58. The composite focal mechanism study of these three swarm sequences revealed right-lateral strike slip faults with horizontal stress axes pattern. The relationship between the lake water level and the swarm sequences showed that both 1987 swarm and 2007 swarm occurred during the decreasing of water level, whereas the 2004 swarm occurred during the increasing of the water level. The study of these three swarm sequences illustrates an interesting phenomena, that there is a seismic quiescence preceding each swarm sequence. The duration period of the seismic quiescence ranges from 3 to 5 months.
Water and pollution transport takes places in fissures, and fissures may also reduce the stability of the rock body. Therefore, fissures in rock are an important issue, especially in case of multi-directional fissure systems, where the situation is more complicated.The so-called azimuthal technique, by using the Schlumberger array is a routinely applied method in geoelectric fissure detections. As we demonstrate it by using analogue model measurements, this method has several shortages. In absence of
information, the fissure directions could be obtained only in 60% of the total cases with a precision of ±10%. We have also demonstrated that the effectivity of the method becomes even worse, when the covering sediment layer is thicker. At the same time, when we simply rejected the anisotropy paradox, it was found, that the effectivity of the method is increasing with increasing sediment thickness. The original azimuthal technique is based on the generally accepted hypothesis of the so-called geoelectric anisotropy paradox. The analogue modelling results have made clear that the critical point of the method is the application of the anisotropy paradox. The fissure directions can only be determined, if the conditions of the anisotropy paradox are clearly defined. However, having more than one fissure directions, statistically these fissure directions can be correctly determined.
The development of the great aurora of January 18, 1770 has been discussed in a fundamental paper by Silberschlag (1770) and other authors. The aurora was observed in middle and low latitudes and in Northern latitude. In Central Europe it displayed all typical auroral forms, including the Corona.
Research activities focusing on the history and philosophy of various sciences are rather heterogeneous. Some disciplines, such as medicine, mathematics, and astronomy, have numerous noteworthy compendia and even specialized journals where papers on their respective history and philosophy can be published. The situation in geophysics, meteorology, and other subdivisions of the geosciences is less favourable. In this essay it is shown that research in the history and philosophy of these sciences requires profound knowledge of many disciplines, including the geosciences. The author intends not only to acquaint a larger circle of geophysicists with the necessity of studying historical aspects in geophysics, but also to stimulate colleagues in the history and philosophy of sciences to contribute to the history of geosciences through their own writings. It is hoped that many scholars in the field of the history and philosophy of science will use the history of geosciences for discussing and studying their own respective fields. The historical commission established in the IAGA deserves the ardent support of researchers in the field, and the establishment of similar commissions or subcommissions in the other associations of IUGG is to be much desired.
Probably the most significant link between research into Earth tides and seismology is connected with the first attempts to measure the Earth’s effective elasticity using these tides. In 1863 William Thomson (Lord Kelvin) published his famous paper “On the rigidity of the Earth”, which describes how these observation could determine the mean rigidity of the Earth. This current paper sets out to describe some important developments in this common area of study between seismology and earth tide research until the middle of the twentieth century.
The modification of Stokes’ formula allows the user to compensate the lack of a global coverage of gravity data by a combination of terrestrial gravity and a global geopotential model. The minimization of the errors of truncation gravity data and potential coefficients could be treated in a least-squares sense as is the basic ingredient in the Royal Institute of Technology (KTH) approach as proposed by Sjöberg in 1984. This article presents the results from a joint project between KTH and the National Land Survey of Sweden, whose main purpose is to evaluate the KTH approach numerically and to compute a gravimetric geoid model for Sweden. The new geoid model (KTH06) was computed based on the least-squares modification of Stokes’ formula, the GRACE global geopotential model, a high-resolution digital terrain model and the NKG gravity anomaly database. The KTH06 was fitted to 1162 GPS/levelling points by a 7-parameter transformation, yielding an all-over fit of 19 mm and 0.17 ppm. The fit is even smaller than the estimated internal accuracy for the geoid model (28 mm). If we assume that the accuracy of the GPS and levelling heights are 10 mm and 5 mm, respectively, it follows that the accuracy of the expected gravimetric geoid heights are of the order of 11 mm. Also, we found a significant expected difference between the KTH06 and NKG2004 models in rough topographic areas (up to 36 cm). As the major ground data and global geopotential model were almost same in the two models, we believe that there are different reasons that come into play for interpreting the discrepancies between them, as the method for eliminating outliers from the gravity database, the interpolated denser gravity observations using the high-resolution digital elevation model before Stokes’ integration, the potential of the LSM kernel, which matches the errors of the terrestrial gravity data, GGM and the truncation error in an optimum way, and the effect of applying more precise correction terms in the KTH approach compared to the remove-compute-restore method. It is concluded that the least-squares modification method with additive corrections is a very promising alternative for geoid computation.