Clustering of mining-induced seismic events in equivalent dimension spaces     

Grzegorz Lizurek  Stanisław Lasocki 《Journal of Seismology》2014,18(3):543-563

High energy release during seismic events induced by mining operation is one of the major dangers perturbing production in underground mines. In this work, temporal changes of seismic event parameters for one of the Rudna Mine (Poland) panels are investigated. The study aim was to find whether the temporal clustering of smaller events in different parameters can be observed before and after the high energy events (M_l?≥?3) in the mining panel. The method chosen for analysis was the study of temporal variation of fractal dimension of the seismic events parameter sets composed from: the interevent epicentral distance (dr), logarithm of seismic energy (lE), and interevent energy coefficient (dlE), which is the absolute difference between logarithms of energy of two consecutive events. Temporal variations study was performed in equivalent dimension (ED) space. The transformation of the seismic source parameters into ED space allowed to estimate and compare the temporal changes of the fractal dimension of different parameter spaces using the same method—correlation fractal dimension, and then easily compare the obtained temporal changes of fractal dimension of different parameter sets. The effect of grouping is expressed by decrease of fractal dimension, which is connected with the similarity of events parameter values. The temporal changes of the fractal dimension of seismicity before the strong induced events would indicate some initiation phase of the process leading to the high energy release. In the case of the studied Rudna Mine panel, the temporal behavior of the fractal dimension values in different parameter spaces before seismic events showed significant changes before three out of four events with CLVD dominant source mechanisms.  相似文献   

Assessment of the Impact of Decis 2.5 EC on the Growth of Hippuris vulgaris          下载免费PDF全文

Małgorzata Gałczyńska  Maria Swarcewicz  Waldemar Paździoch  Teresa Lewandowska 《洁净——土壤、空气、水》2016,44(10):1329-1334

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Application of Multichannel Analysis of Surface Waves to S-Phase Wave Anisotropy Estimation     

Iwona Stan-Kłeczek  Maciej J. Mendecki 《Acta Geophysica》2016,64(5):1593-1604

The Multichannel Analysis of Surface Waves (MASW) is an increasingly used technique for recognition of a shallow geological structure and estimation of geotechnical parameters, e.g., S-wave velocity, layer density, layer thickness, shear modulus, estimated P-wave velocity, and estimated Poisson ratio. MASW surveys were carried out in two limestone quarries in the southern part of Poland. The experimental areas are characterised by a simple geological structure: consolidated Triassic limestone. Measurement profiles were arranged as a shapely six-pointed star. For each survey line, 12 geophones with 2-meter (Deposit 1) and 3-meter (Deposit 2) spacing were applied. The research allowed to compare P- and S-wave velocity changes with the main crack systems in the studied rock masses.  相似文献   

The influence of meander bend evolution on the formation of multiple cutoffs: findings inferred from floodplain architecture and bend geometry          下载免费PDF全文

Marcin Słowik 《地球表面变化过程与地形》2016,41(5):626-641

The evolution of meander bends and formation of cutoffs, including a series of cutoffs developed simultaneously in a number of bends, have been investigated by many researchers. However, relatively little is known about factors that lead to the development of multiple cutoffs that are formed subsequently at one location. The present study aims to determine the influence of meander bend development on multiple chute cutoff formation in a single bend. The research is based on the sedimentary record of meander migration and cutoffs preserved in a lowland river floodplain (the lower Obra River, Poland). Analysis of changes in meander geometry was conducted to describe the influence of their migration on cutoff formation and in other rivers where multiple cutoffs occurred. The results showed that multiple cutoffs in the lower Obra River have occurred during the last 3000 years, owing to the interaction of upstream and downstream controls: migration of meander bends in opposing directions accompanied by an increase of flood frequency and sediment supply. The flow and sediment supply has been further altered since the nineteenth century due to anthropogenic impacts: an artificial cutoff of the downstream bend and elevation of channel levées. Similar mechanisms driving the formation of multiple cutoff have been found in other river courses, despite significantly higher energy of the compared rivers. Moreover, development of a confined‐shape bend (caused by artificial barrier or autogenic bend behaviour) may also favour the formation of multiple cutoffs. However, counter migration of meanders enhanced by increased flood frequency and sediment supply are primary triggers for such events. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Resik: A Bent Crystal X-ray Spectrometer for Studies of Solar Coronal Plasma Composition     

J. Sylwester  I. Gaicki  Z. Kordylewski  M. Kowaliński  S. Nowak  S. Płocieniak  M. Siarkowski  B. Sylwester  W. Trzebiński  J. Bakała  J. L. Culhane  M. Whyndham  R. D. Bentley  P. R. Guttridge  K. J. H. Phillips  J. Lang  C. M. Brown  G. A. Doschek  V. D. Kuznetsov  V. N. Oraevsky  A. I. Stepanov  D. V. Lisin 《Solar physics》2005,226(1):45-72

We describe the RESIK (REntgenovsky Spektrometr s Izognutymi Kristalami) instrument, consisting of two double-channel X-ray spectrometers, designed to observe solar active region and flare plasmas. RESIK is one of the instruments making up the scientific payload of the Russian CORONAS-F solar mission. The uncollimated spectrometer uses two silicon and two quartz bent crystals observing flare, active region and coronal spectra in four wavelength bands with a resolving power (/ ) of 1000. The wavelength coverage, 3.3–6.1 Å, includes emission lines of Si, S, Cl, Ar, and K and in the third diffraction order, the wavelength range includes He-like Fe lines (1.85 Å) and Ni lines (1.55 Å) with dielectronic satellites, emitted during intense, hot flares. The instrument is believed to be the best calibrated space-borne crystal spectrometer flown to date. The spectrometer dynamically adjusts the data gathering intervals from 1 s to 5 minutes, depending on the level of solar X-ray emission at the time of observation. The principal aims of RESIK are the measurements of relative and absolute element abundances in the emitting plasma and the temperature distribution of plasma (differential emission measure) over the temperature interval 3 and 50 MK. This paper summarizes the scientific objectives of RESIK and describes the design, characteristics, and performance of the instrument.  相似文献   

On the cosmological red shift     

Stanisław Bellert 《Astrophysics and Space Science》1970,7(2):211-230

The paper is an extension of this author's hypothesis, presented inAstrophys. Space Sci. 3 (1969), 268, which explains the red shift in terms of a geometry of static space and stationary observers. The author introduces here the notions of metric with an observer, observed distance and space of observations; he considers the problem of the equivalence of stationary observers and discusses the relation between the hypothesis, the special theory of relativity and Maxwell equations. Attention is drawn to the agreement between the hypothesis and the experimental results discussed by Shamir and Fox, and those discussed by Kennedy and Thorndike.  相似文献   

Lunisolar Resonances Revisited     

Sławomir Breiter 《Celestial Mechanics and Dynamical Astronomy》2001,81(1-2):81-91

Lunisolar resonances arise in the artificial satellite problem without short-periodic terms. The basic model including the Earth's J ₂and a Hill-type model for the Sun or the Moon admits 20 different periodic terms which may lead to a resonance involving the satellite's perigee, node and the longitude of the perturbing body. Some of the resonances have been studied separately since 1960s. The present paper reviews all single resonances, attaching an appropriate fundamental model to each case. Only a part of resonances match known fundamental models. An extended fundamental model is proposed to account for some complicated phenomena. Most of the double resonance cases still remain unexplored.  相似文献   

Contamination of tsunami sediments in a coastal zone inundated by the 26 December 2004 tsunami in Thailand     

Witold Szczuciński  Przemysław Niedzielski  Grzegorz Rachlewicz  Tadeusz Sobczyński  Anetta Zioła  Artur Kowalski  Stanisław Lorenc  Jerzy Siepak 《Environmental Geology》2005,49(2):321-331

Tsunami sediments deposited in a coastal zone of Thailand by the 26 December 2004 tsunami wave were sampled within 50 days after the event. All surface and ground waters in tsunami- inundated zone revealed significant salinity at that time. The tsunami sediments, composed mainly of fine to medium sand, contain significantly elevated contents of salts (Na⁺, K⁺, Ca⁺², Mg⁺², Cl and SO ₄ ⁻² ) in water-soluble fraction, and of Cd, Cu, Zn, Pb in the bioavailable fraction and As in the exchangeable fraction in relation to the reference sample. The origin of contaminants is marine, as well as litho- and anthropogenic. The salts and Pb, Zn and Cu reveal high correlation to each other and to the mean grain size (pore size and porosity). Serious environmental hazard exists in that region because, due to gentle morphology, there is a risk of migration of the contaminants into ground waters and food chain.  相似文献   

On the relationship between refractive index and density for SiO2 polymorphs     

Sławomir Maj 《Physics and Chemistry of Minerals》1984,10(3):133-136

The Gladstone-Dale law (specific refraction) and the Drude law (molecular refraction) for silica polymorphs, at “sodium light” (λ _D =0.5893 μm), are derived from simple atomic properties of SiO₂ complex (atomic weight, first ionization potential). The considerations are based on the Lorentz electron theory of solids. The characteristic frequency (or eigenfrequency) v ₀ of elementary electron oscillators (in energy units, hv) is identified with the band gap E _G of a solid; on the other hand, this E _G -gap is identified with the single ionization potential \(\tilde U\) of non-free atoms. For \(\tilde U\) =E _G =10.2 eV (energy gap of quartz, see Nitsan and Shankland 1976b) the Gladstone-Dale law, or specific refraction, is (n?1)/ρ=0.208 cm³/g, where n and ρ are the refractive index and the density of medium, respectively. According to empirical data, the average value of the specific refraction of pure SiO₂ polymorphs (except stishovite-high density phase of silica) is (〈n〉?1)/ρ=0.207±0.001 (〈n〉 denotes the mean refractive index of crystal). For stishovite the Drude law (n ²?1)/ρ=0.542 cm³/g is valid under an assumption that the first ionization potential \(\tilde U\) =E _G ≈9 eV; this result is good agreement with the empirical value (〈n〉²?1)/ρ=0.536 cm³/g.  相似文献   

Problems of migration of Polish crude oils on the basis of geochemical correlation data and carbon isotope composition     

A Marzec  H Kozikowski  J Głogoczowski  W Kisielow 《Chemical Geology》1971

A method for the correlation of crude oils has been worked out on the basis of analyses of 120 crude oils from 4 geological regions of Poland.  相似文献