A Study of Spatial Distribution of Induced Seismicity in the Upper Silesian Coal Basin   总被引：1，自引：0，他引：1  

Adam Filip Idziak 《Natural Hazards》1999,19(2-3):97-105

The Upper Silesian Coal Basin (USCB) is a region where high seismic activity is observed. Most of these seismic events have a local magnitude not exceeding 2.3. Their location and type of focal mechanism suggest that they are connected with new discontinuities in the rock mass caused by mining activity. Shocks with higher magnitude are also observed but their frequency is much lower. The strong events have a different focal mechanism than the low energetic events. The spatial distribution of shock epicentres is not uniform in the USCB area and shows the fractal character of seismic phenomena. Despite extensive mining activity throughout the area, the epicentres of strong events are concentrated in four regions belonging to different geological units. The temporal variability of epicentre co-ordinates and the general decrease of seismic activity points to the migration of seismicity across the investigated area. Analysing the spatial and temporal distributions of the strongest shocks, one can suppose this area to be critically self-organised. These facts suggest that induced seismicity in the USCB is triggered by a nonlinear dynamic process, having regional character and connected with recent tectonic activity.  相似文献   

On possible fluid detection in equivalent transversely isotropic media     

Filip P. Adamus 《Geophysical Prospecting》2019,67(9):2319-2331

We consider a transversely isotropic medium that is long-wave equivalent to a stack of thin, parallel, isotropic layers and is obtained using the Backus average. In such media, we analyse the relations among anisotropy parameters; Thomsen parameters, ε and δ, and a new parameter ϕ. We discuss the last parameter and show its essential properties; it equals 0 in the case of isotropy of equivalent medium and/or constant Lamé coefficient λ in layers. The second property occurs to make ϕ sensitive to variations of λ in thin-bedded sequences. According to Gassmann, in isotropic media the variation of fluid content affects only the Lamé coefficient λ, not μ; thus, the sensitivity to changes of λ is an essential property in the context of possible detection of fluids. We show algebraically and numerically that ϕ is more sensitive to these variations than ε or δ. Nevertheless, each of these parameters is dependent on the changes of μ; to understand this influence, we exhibit comprehensive tables that illustrate the behaviour of anisotropy parameters with respect to specific variations of λ and μ. The changes of μ in layers can be presented by the Thomsen parameter γ that depends on them solely. Hence, knowing the values of elasticity coefficients of equivalent transversely isotropic medium, we may compute ϕ and γ, and based on the aforementioned tables, we predict the expected variation of λ; in this way, we propose a new method of possible fluid detection. Also, we show that the prior approach of possible detection of fluids, proposed by Berryman et al., may be unreliable in specific cases. To establish our results, we use the Monte Carlo method; for the range and chosen variations of Lamé coefficients λ and μ – relevant to sandstones – we generate these coefficients in thin layers and, after the averaging process, we obtain an equivalent transversely isotropic medium. We repeat that process numerous times to get many equivalent transversely isotropic media, and – for each of them  – we compute their anisotropy parameters. We illustrate ϕ, ε and δ in the form of cross-plots that are relevant to the chosen variations of λ and μ. Additionally, we present a table with the computed ranges of anisotropy parameters that correspond to different variations of Lamé coefficients.  相似文献   

Correlation studies on an RC frame shaking-table specimen     

Angelo d'Ambrisi  Filip C. Filippou 《地震工程与结构动力学》1997,26(10):1021-1040

This paper presents the correlation of the results of a new model for the dynamic analysis of reinforced concrete (RC) frames with the experimental time history of a two storey RC frame shaking-table specimen. The frame member model consists of separate subelements that describe the deformations due to flexure, shear and bond slip in RC structural elements. The subelements are combined by superposition of flexibility matrices to form the frame element. A non-linear solution method which accounts for the unbalance of internal forces between different subelements during a given load increment is used with the model. The ability of the proposed model to describe the dynamic response of frame structures under earthquake excitations is evaluated by comparing the analytical results with experimental evidence from a two-storey, one bay reinforced concrete frame tested on the shaking-table. The model parameters for the shaking-table specimen are derived from available experimental evidence and first principles of reinforced concrete. The effect of reinforcing bar slip on the local and global dynamic response of the test structure is assessed. © 1997 John Wiley & Sons, Ltd.  相似文献   

Response of braiding channel morphodynamics to peak discharge changes in the Upper Yellow River          下载免费PDF全文

Filip Schuurman  Wanquan Ta  Sander Post  Marius Sokolewicz  Marcela Busnelli  Maarten Kleinhans 《地球表面变化过程与地形》2018,43(8):1648-1662

The braiding intensity and dynamics in large braiding rivers are well known to depend on peak discharges, but the response in braiding and channel–floodplain transformations to changes in discharge regime are poorly known. This modelling study addresses the morphodynamic effects of increasing annual peak discharges in braiding rivers. The study site is a braiding reach of the Upper Yellow River. We estimated the effects on the larger‐scale channel pattern, and on the smaller‐scale bars, channel branches and floodplains. Furthermore, we determined the sensitivity of the channel pattern to model input parameters. The results showed that the dominant effect of a higher peak discharge is the development of chute channels on the floodplains, formed by connecting head‐cut channels and avulsive channels. Widening of the main channel by bank erosion was found to be less dominant. In addition, sedimentation on the bars and floodplains increased with increasing peak discharge. The model results also showed that the modelled channel pattern is especially sensitive to parametrization of the bed slope effect, whereas the effect of median grain size was found to be relatively small. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

A damage model for structures with degrading response          下载免费PDF全文

Thanh. N. Do  Filip. C. Filippou 《地震工程与结构动力学》2018,47(2):311-332

The paper presents a hysteretic damage model for the response simulation of structural components with strength and stiffness deterioration under cyclic loading. The model is based on 1D continuum damage mechanics and relates any 2 work‐conjugate response variables such as force‐displacement, moment‐rotation, or stress‐strain. The strength and stiffness deterioration is described by a continuous damage variable. The formulation uses a criterion based on the hysteretic energy and the maximum or minimum deformation for damage initiation with a cumulative probability distribution function for the damage evolution. A series of structural component response simulations showcase the ability of the model to describe different types of hysteretic behavior. The relation of the model's damage variable to the Park‐Ang damage index is also discussed. Because of its consistent and numerically robust formulation, the model is suitable for the large‐scale seismic response simulation of structural systems with strength and stiffness deterioration.  相似文献   

Ageing of Dissolved Halogenated Humic Substances and the Microbiological Influence on this Process     

K. G. Heumann  G. Rdlinger  M. Erbes  I. Heiber  U. Obst  Z. Filip  H. Claus 《洁净——土壤、空气、水》2000,28(4):193-201

The distribution of halogens in various fractions of humic substances (HS), separated by their molecular weight, was found to be different for the different halogens. This was demonstrated for chlorine, bromine, and iodine in sewage and brown water samples by applying inductively coupled plasma mass spectrometry coupled with size‐exclusion chromatography. Quantification of the different fractions of iodinated humic substances was obtained by quadrupole mass spectrometry in connection with the isotope dilution technique using an ¹²⁹I‐enriched spike solution. Quantitative analysis was not possible for the corresponding chlorine and bromine species because of spectrometric interferences in the quadrupole instrument. The ageing of HS/halogen species was followed with respect to possible transformations of these species in a ground and sewage water sample up to eight weeks. Even if a distinct structural variation of the humic substance was observed with time by measuring the UV absorption, chlorine remained in the same molecular weight fraction and only a small change was found for the HS/bromine species after eight weeks. In contrast to these findings a substantial transformation of HS/iodine compounds took place, which demonstrated that the transfer probability of halogens from one to another HS fraction is increased with decreasing strength of the halogen bond to carbon. By comparing the results of an original sewage water sample with a filtered one and with another one which was enriched by microorganisms cultivated from the same original sample, a strong microbiological influence on the transformation of HS/iodine species was found. A quantitative balance of the corresponding HS/iodine fractions was calculated for an ageing period of eight weeks showing that iodine was preferably transferred to newly formed UV active HS substances of high molecular weight. In total, no iodine was released from the humic substances.  相似文献   

Degradation and Transformation of Aquatic Humic Substances by Laccase-producing Fungi Cladosporium cladosporioides and Polyporus versicolor     

H. Claus  Z. Filip 《洁净——土壤、空气、水》1998,26(3):180-185

A phenoloxidase-producing fungus – Cladosporium cladosporioides – was isolated from water of a bog lake. At high concentrations of carbon (333 mM) and nitrogen (12 mM), the fungus demonstrated the formation of a laccase and a high ligninolytic activity. After addition of riverine or groundwater humic substances into culture media (ca. 1 mg mL^–1), the fungus showed the ability of degrading (utilizing) of about 60% of these substances. However, the exact quantification of the degree of degradation was difficult because of adsorption of humic matter on fungal mycelium. Reisolated humic substances were lower in aromatic and higher in aliphatic structures. A crude enzyme from the C. cladosporioides culture showed only low activity in decolorizing humic substances, whereas decolorization up to 50% was observed when using a laccase preparation from Polyporus versicolor, and especially in the presence of a redox mediator.  相似文献   

Secondary arsenic minerals and arsenic mobility in a historical waste rock pile at Kaňk near Kutná Hora,Czech Republic     

E. Kocourková-Víšková  J. Loun  O. Sracek  S. Houzar  J. Filip 《Mineralogy and Petrology》2015,109(1):17-33

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Erratum to: Application of landslide hazard scenarios at annual scale in the Niraj River basin (Transylvania Depression,Romania)     

Roşca Sanda  Bilaşco Ştefan  Petrea Dănuţ  Fodorean Ioan  Vescan Iuliu  Filip Sorin 《Natural Hazards》2015,77(3):1593-1593

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Blue, complexly zoned, (Na,Mg,Fe,Li)-rich beryl from quartz-calcite veins in low-grade metamorphosed Fe-deposit Sk��ly near Ryma?ov, Czech Republic     

Milan Nov��k  Petr Gadas  Jan Filip  Tom��? Vaculovi?  Jan P?ikryl  Bohuslav Fojt 《Mineralogy and Petrology》2011,102(1-4):3-14

Syn-tectonic quartz-calcite veins containing blue beryl are enclosed in hematite > magnetite-rich portions of the low-grade metamorphosed Fe-deposit Skály near Ryma?ov, Czech Republic. Aggregates of pale to deep blue beryl, up to 2?cm in diameter, are associated with euclase, clinochlore, hematite, albite and dravite. Complexly zoned beryl crystals consist of skeletal aggregates of beryl I randomly distributed within volumetrically dominant beryl II with narrow rims of beryl III. All types of beryl have similar contents of Na (0.32?C0.49 apfu) and Mg (0.31?C0.41 apfu) but variable contents of Fe_tot (0.05?C0.34 apfu) and Al (1.20?C1.62 apfu). The LA-ICP-MS study yielded elevated contents of Li, up 1,314?ppm (0.28?wt.% Li₂O) in beryl I. The quartz-calcite veins represent an unusual type of low-T metamorphic-hydrothermal vein related to Fe-ore deposit characterized by single-stage fracturing and mobilization in a closed system at T~200?C300°C and CO ₃ ^2- as a major complexing agent for the mobility of Be.  相似文献