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Spatial variations of the magnetic field, measured at the Earth's surface, are mainly due to geological inhomogeneities within the crust. The present state of the crust, in turn, reflects its past dynamical processes and evolution. We analyzed the magnetic field intensity along a few but densely sampled profiles in a Tertiary volcanic province near Bonn, Germany. The aim was to find out whether the variation of the magnetic intensity can be related to a deterministic, although chaotic, generating system or to a stochastic one. In the former case, the geodynamical history would depend on a few degrees of freedom, whereas in the latter case, the parameters to take into account were so many that a statistic approach appears to be more suitable. Since strange attractors do not emerge from the analyzed data, we exclude the presence of a chaos generating system. Autocorrelation functions and a rescaled-range analysis, on the other hand, reveal and quantify a certain degree of correlation among successive data points and allow calculation of a range of spectral exponents in log-log diagrams, which are clearly distinct from those of white noise and Brownian motion. Only one of the profiles exhibits similarity to uncorrelated or white noise. In this case, the signal variations do not result from the local geology but from a buried gas pipe-line, aligned subparallel to that profile. If self-organized crustal evolution generally produces signatures that can be described as correlated noise, within a limited bandwidth of spectral exponents, erraneous or disturbed data could eventually be discriminated from records containing purely natural data by applying analysis tools of the dynamic system theory together with autocorrelation tests. 相似文献
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Prof. Piero Leonardi 《International Journal of Earth Sciences》1964,53(1):101-112
Zusammenfassung Die Struktur der Dolomiten paßt ausgezeichnet in das tektonische Bild der südlichen Alpen, wenn auch das Vorhandensein der permischen Porphyrplatte stellenweise häufig Brüche verursacht hat.Die Dislokationen der Dolomiten folgen im allgemeinen Falten und Faltenverwerfungen, die von Westen nach Osten verlaufen und vorwiegend eine Vergenz nach Süden aufweisen.Die permische Porphyrplatte und die markanten Linsen der Dolomitriffe machen diese Gegend zu einem klassischen Beispiel selektiver Tektonik.Die Tektonik der Dolomiten beruht z. T. auf Ablösungs- und Gleiterscheinungen an geneigten Flächen. Es gibt zahlreiche Falten und Brüche im kristallinen Unterbau, die anscheinend durch Druck entstanden sind.
The structure of the Dolomite-unit easily fits into the tectonic framework of the Southern Alps even if the Permian porphyry plate locally produced more fracturing.The dislocations of the Dolomites, in general, corresponds to West-Eastorientated folds and faulted overfolds. The porphyry plate mentioned and the rigid lenses of the Dolomites reefs have produced classic examples of selective tectonics.Tectonic of the Dolomites is due in part to decollements and sliding from inclined planes, but decollement surfaces of a regional nature are excluded, and the dislocations of the Dolomites-region are not only epidermic.Numerous folds and fractures intersect the basement as well and seem compressive.
Résumé La structure des Dolomites s'intègre remarquablement bien dans le plan tectonique des Alpes Méridionales, bien que la présence de la dalle porphyrique permienne ait fréquemment, par endroit, provoqué des ruptures. Les dislocations des Dolomites font suite en général à des plis et à des plis-failles avec axes allant d'Ouest en Est et montrant de façon prédominante un déversement vers le Sud.La dalle porphyrique permienne et les lentilles des récifs des Dolomites font de cette région un exemple classique de «tectonique sélective». La tectonique des Dolomites repose en partie sur des phénomènes de décollement et de glissement le long de surfaces inclinées. Il y a de nombreux plis et fractures dans le soubassement cristallin qui, semble-t-il, résultent d'une compression.
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In this paper a semiparametric approach is introduced to decompose an ARFIMA model in the long memory and short memory unobserved components. The procedure is based on the DECOMEL method which produces a statistical decomposition by minimizing the Euclidean distance between the spectrum of the aggregated series and the sum of the parametric spectra of the components. The extension to long memory stationary models is achieved defining an approximate model where the fractional operator is replaced by the ratio of two polynomials of order one. The feasibility and performance of the proposed procedure are discussed through a case study. 相似文献
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Martino Amodio Paolo Bruno Maurizio Caselli Gianluigi de Gennaro Paolo Rosario Dambruoso Barbara Elisabetta Daresta Pieirna Ielpo Francesco Gungolo Claudia Marcella Placentino Vincenzo Paolillo Maria Tutino 《Atmospheric Research》2008,90(2-4):313-ICNAA07
Some peak PM10 episodes, occurred during PM monitoring campaigns performed on October 2005 and February and June 2006 in Bari town, have been characterized. Moreover back trajectories of air masses and Principal Component Analyses were applied. Three of the peak PM10 episodes investigated were related to local emissions of primary pollutants during poor atmospheric dispersion conditions. The other two peak PM10 episodes considered are related with long range transport air masses toward Apulia region: in one case the chemical characterization and the back trajectories analysis indicate that high PM10 value detected is due to the Saharan dust advection in the Apulia region; in the other case air masses with different origin give rise to high PM10 value.Moreover PM10 daily mean concentrations, presented in this paper collected from January 2005 to August 2007 and obtained by automatic device in six stations of air quality monitoring networks in Bari territory, do not show a seasonal trend for PM10 concentrations, contrary to the PM10 trend shown in the towns of North Italy. This can be explained mostly considering that our region presents generally meteo-climatic conditions that favour pollutants dispersion. 相似文献
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Oliver Hahn Cristiano Porciani Avishai Dekel C. Marcella Carollo 《Monthly notices of the Royal Astronomical Society》2009,398(4):1742-1756
We explore a possible origin for the puzzling anti-correlation between the formation epoch of galactic dark-matter haloes and their environment density. This correlation has been revealed from cosmological N -body simulations and is in conflict with the extended Press–Schechter model of halo clustering. Using similar simulations, we first quantify the straightforward association of an early formation epoch with a reduced mass-growth rate at late times. We then find that a primary driver of suppressed growth, by accretion and mergers, is tidal effects dominated by a neighbouring massive halo. The tidal effects range from a slowdown of the assembly of haloes due to the shear along the large-scale filaments that feed the massive halo to actual mass loss in haloes that pass through the massive halo. Using the restricted three-body problem, we show that haloes are prone to tidal mass loss within 1.5 virial radii of a larger halo. Our results suggest that the dependence of the formation epoch on environment density is a secondary effect induced by the enhanced density of haloes in filaments near massive haloes where the tides are strong. Our measures of assembly rate are particularly correlated with the tidal field at high redshifts z ∼ 1 . 相似文献
9.
Structural controls on fractured coal reservoirs in the southern Appalachian Black Warrior foreland basin 总被引：1，自引：0，他引：1
Richard H. Groshong Jr. Jack C. Pashin Marcella R. McIntyre 《Journal of Structural Geology》2009,31(9):874
Coal is a nearly impermeable rock type for which the production of fluids requires the presence of open fractures. Basin-wide controls on the fractured coal reservoirs of the Black Warrior foreland basin are demonstrated by the variability of maximum production rates from coalbed methane wells. Reservoir behavior depends on distance from the thrust front. Far from the thrust front, normal faults are barriers to fluid migration and compartmentalize the reservoirs. Close to the thrust front, rates are enhanced along some normal faults, and a new trend is developed. The two trends have the geometry of conjugate strike-slip faults with the same σ1 direction as the Appalachian fold-thrust belt and are inferred to be the result of late pure-shear deformation of the foreland. Face cleat causes significant permeability anisotropy in some shallow coal seams but does not produce a map-scale production trend. 相似文献
10.
Matteo Correnti Francesco Paresce Rossella Aversa Giacomo Beccari Guido De Marchi Marcella Di Criscienzo Xiaoying Pang Loredana Spezzi Elena Valenti Paolo Ventura 《Astrophysics and Space Science》2012,340(2):263-279
We have used new, deep, visible and near infrared observations of the compact starburst cluster in the giant HII region NGC 3603 and its surroundings with the WFC3 on HST and HAWK-I on the VLT to study in detail the physical properties of its intermediate mass (∼1–3 M⊙) stellar population. We show that after correction for differential extinction and actively accreting stars, and the study of field star contamination, strong evidence remains for a continuous spread in the ages of pre-main sequence stars in the range ∼2 to ∼30 Myr within the temporal resolution available. Existing differences among presently available theoretical models account for the largest possible variation in shape of the measured age histograms within these limits. We also find that this isochronal age spread in the near infrared and visible Colour-Magnitude Diagrams cannot be reproduced by any other presently known source of astrophysical or instrumental scatter that could mimic the luminosity spread seen in our observations except, possibly, episodic accretion. The measured age spread and the stellar spatial distribution in the cluster are consistent with the hypothesis that star formation started at least 20–30 Myrs ago progressing slowly but continuously up to at least a few million years ago. All the stars in the considered mass range are distributed in a flattened oblate spheroidal pattern with the major axis oriented in an approximate South-East–North-West direction, and with the length of the equatorial axis decreasing with increasing age. This asymmetry is most likely due to the fact that star formation occurred along a filament of gas and dust in the natal molecular cloud oriented locally in this direction. 相似文献