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Artykuły w czasopismach na temat "Seismic signal effect"
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Limberger, Fabian, Georg Rümpker, Michael Lindenfeld i Hagen Deckert. "The impact of seismic noise produced by wind turbines on seismic borehole measurements". Solid Earth 14, nr 8 (18.08.2023): 859–69. http://dx.doi.org/10.5194/se-14-859-2023.
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Abstract. Seismic signals produced by wind turbines can have an adverse effect on seismological measurements up to distances of several kilometres. Based on numerical simulations of the emitted seismic wave field, we study the effectivity of seismic borehole installations as a way to reduce the incoming noise. We analyse the signal amplitude as a function of sensor depth and investigate effects of seismic velocities, damping parameters and geological layering in the subsurface. Our numerical approach is validated by real data from borehole installations affected by wind turbines. We demonstrate that a seismic borehole installation with an adequate depth can effectively reduce the impact of seismic noise from wind turbines in comparison to surface installations. Therefore, placing the seismometer at greater depth represents a potentially effective measure to improve or retain the quality of the recordings at a seismic station. However, the advantages of the borehole decrease significantly with increasing signal wavelength.
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Howie, John A., i Ali Amini. "Numerical simulation of seismic cone signals". Canadian Geotechnical Journal 42, nr 2 (1.04.2005): 574–86. http://dx.doi.org/10.1139/t04-120.
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Numerical analysis can provide insight into the effect of ground conditions on seismic signals recorded in downhole seismic testing. As part of a study of the interpretation of seismic cone data in complex ground conditions, this paper deals with the cases of wave propagation in (i) homogeneous soil and (ii) soil of increasing stiffness with depth. The main purpose of this study was to assess the validity of the use of the finite difference program FLAC for the simulation of the downhole seismic test. For realistic assumptions of material stiffness and damping, the main characteristics of field seismic cone penetration test (SCPT) seismic data were reproduced in the simulated data. Both displayed the same general shape of signal, number of oscillations, signal attenuation, frequency content, compression wave component (near-field effect), signal widening, and shift of the peak of the frequency spectrum with depth. Damping was shown to cause signal widening and dispersion, and the shear wave velocity, Vs, interpreted from the simulated wave traces varied with the interval method used to determine it. For a case history of field data, it was found that Vs varied by about 3%, depending on the analysis method used. The results show that finite difference modeling of wave propagation can provide useful insights into the factors affecting the interpretation of downhole seismic tests.Key words: seismic cone testing, shear wave velocity, signal widening, near-field effect, numerical simulation, finite difference.
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Zhang, Xingli, Yan Chen, Ruisheng Jia i Xinming Lu. "Two-dimensional variational mode decomposition for seismic record denoising". Journal of Geophysics and Engineering 19, nr 3 (1.06.2022): 433–44. http://dx.doi.org/10.1093/jge/gxac032.
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Abstract Seismic signal denoising is the main task of seismic data processing. This study proposes a novel method for the denoising seismic record on the basis of a two-dimensional variational mode decomposition (2D-VMD) algorithm and permutation entropy (PE). 2D-VMD is a recently introduced adaptive signal decomposition method in which $K$ and $\alpha $ are important decomposing parameters to determine the number of modes, and have a predictable effect on the nature of detected modes. We present a novel method to address the problems of selecting appropriate $K$ and $\alpha $ values and apply these values to the proposed method. First, for a 2D seismic signal, the 2D-VMD method can decompose it into $K$ modes with specific direction and vibration characteristics. Next, the PE value of each mode is calculated. Random noise components are eliminated according to the PE value. Finally, the signal components are reconstructed to acquire the denoised seismic signal. Experimental and simulation results indicate that the proposed method has remarkable denoising effect on synthetic and real seismic signals. We hope that this new method can inspire and help evaluate new ideas in this field.
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Landrø, Martin. "The effect of noise generated by previous shots on seismic reflection data". GEOPHYSICS 73, nr 3 (maj 2008): Q9—Q17. http://dx.doi.org/10.1190/1.2894453.
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In marine seismic acquisition, the typical time interval between two adjacent shots is about [Formula: see text]. This interval is considered sufficient to avoid the signal from one shot interfering with the signal from the next shot. However, when we are looking for very weak signals or weak changes in a given signal (time-lapse seismic), the influence of the shot-generated noise can be of importance. In the present work, shot records with a recording time of [Formula: see text] are used to analyze the influence of the shot-generated noise from the previous shot. Simple decay models are used to match the observed rms decay curves. These calibrated models are used to estimate variations in signal-to-noise ratio versus shot time interval and source strength. For instance, if the source strength is doubled and the time interval between two shots is increased from [Formula: see text], an improvement in the signal-to-shot-generated noise from the previous shot of [Formula: see text] is expected. Especially for time-lapse seismic using permanently installed receivers, this way of increasing the S/N might be useful.
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Li, Bo, Lixin Zhang, Qiling Zhang i Shengmei Yang. "An EEMD-Based Denoising Method for Seismic Signal of High Arch Dam Combining Wavelet with Singular Spectrum Analysis". Shock and Vibration 2019 (10.03.2019): 1–9. http://dx.doi.org/10.1155/2019/4937595.
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Due to complicated noise interference, seismic signals of high arch dam are of nonstationarity and a low signal-to-noise ratio (SNR) during acquisition process. The traditional denoising method may have filtered effective seismic signals of high arch dams. A self-adaptive denoising method based on ensemble empirical mode decomposition (EEMD) combining wavelet threshold with singular spectrum analysis (SSA) is proposed in this paper. Based on the EEMD result for seismic signals of high arch dams, a continuous mean square error criterion is used to distinguish high-frequency and low-frequency components of the intrinsic mode functions (IMFs). Denoised high-frequency IMF using wavelet threshold is reconstructed with low-frequency components, and SSA is implemented for the reconstructed signal. Simulation signal denoising analysis indicates that the proposed method can significantly reduce mean square error under low SNR condition, and the overall denoising effect is superior to EEMD and EEMD-Wavelet threshold denoising algorithms. Denoising analysis of measured seismic signals of high arch dams shows that the performance of denoised seismic signals using EEMD-Wavelet-SSA is obviously improved, and natural frequencies of the high arch dams can be effectively identified.
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Zheng, Gong Ming, Yuan Yuan Shen i Ling Ling Song. "Vibroseis Nonlinear Scanning Signal Simulation Analysis". Applied Mechanics and Materials 318 (maj 2013): 191–95. http://dx.doi.org/10.4028/www.scientific.net/amm.318.191.
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Vibrator nonlinear scan is an important means of high frequency seismic exploration. With the propagation of seismic waves, High frequency components continue to be absorbed, due to the filtering effect of the earth. Nonlinear scanning technology can get some degree of compensation to the seismic wave loss in the high frequency part in the propagation, by extending the vibration of the high frequency component time. This article through MATLAB simulation, this paper analyzed the nonlinear scanning signals in scanning signals and logarithmic index scanning signals, and the similarities and differences between the two signals are summarized.
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Cai, Jianxian, Li Wang, Jiangshan Zheng, Zhijun Duan, Ling Li i Ning Chen. "Denoising Method for Seismic Co-Band Noise Based on a U-Net Network Combined with a Residual Dense Block". Applied Sciences 13, nr 3 (19.01.2023): 1324. http://dx.doi.org/10.3390/app13031324.
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To address the problem of waveform distortion in the existing seismic signal denoising method when removing co-band noise, further improving the signal-to-noise ratio (SNR) of seismic signals and enhancing their quality, this paper designs a seismic co-band denoising model Atrous Residual Dense Block U-Net (ARDU), which uses a U-shaped convolutional neural network (U-Net) as a basic framework and combines atrous convolution and the residual dense block (RDB). In the ARDU model, atrous convolution is connected with residual dense blocks to form the feature extraction unit of the model encoder. Among them, the residual dense blocks can deepen the network’s depth and enhance the feature extraction ability of the network on the premise of mitigating the gradient-vanishing and gradient-exploding problem. Atrous convolution can enlarge receptive fields, reduce waveform distortion, and protect effective signals without increasing network parameters. To test the denoising performance of the ARDU model, the Stanford Global Seismic dataset was used to construct a training set and a test set and the model was trained and tested on it. The experimental results of the ARDU model for different types of seismic co-band noise showed that this model can effectively remove seismic co-band noise, protect effective signals, improve the SNR of seismic signals, and enhance the quality of seismic signals. To further verify the denoising effect of the model, this model was compared with the wavelet threshold denoising U-Net model and the denoising residual dense block (DnRDB) model, and the results showed that the ARDU model has the best SNR, r (correlation coefficient), and root-mean-square error (RMSE) and the least distortion of the seismic signal waveform.
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Juarzan, Laode Ihksan. "ANALISIS SINYAL SEISMIK DAN SELF POTENTIAL (SP) DARI FENOMENA SEIMOELEKTRIK DI GUNUNG LUMPUR BLEDUG KUWU JAWA TENGAH". Jurnal Rekayasa Geofisika Indonesia 4, nr 01 (30.04.2022): 60. http://dx.doi.org/10.56099/jrgi.v4i01.27456.
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Abstarct Bledug Kuwu is one of the mud volcano (gunung lumpur) in Java. Bledug Kuwu eruption periodically occured with a frequency of more than five times in one minute, pointed by the release of gas bubbles and mud. This study aims to observe the signals of the seismic and self potential (SP) from seismoelectric phenomenon generated by Bledug Kuwu eruption. Measurements were performed by placed seismic sensor around the main crater point of Bledug Kuwu mud volcano, while the SP sensor placed in the vertical, the radial and tangential direction from the point of the main crater of a Bledug Kuwu mud volcano.. The result of analysis shows that the dominant frequency of seismic events is 0,2 Hz, while dominant frequency of SP signals is 48,0 Hz. The arrival time difference between seismic and SP signals predominantly in the range of time (0,0 to 1,5 second) which indicates that the appears of the seismic signal causes the appearance of the signal SP as a result of the transfer fluid as described in the seismoelectric phenomenon.The average value of the amplitude of seismic events for Z, NS and EW component is 0,6694, 0,4848 and 0,5158 Count/Volt. The average value of the amplitude of SP events for Z, NS and EW component is 1,338, 1,249 and 0,909 mVolt. SP events will appear if amplitude of seismic events more than 0,2 Count value. Amplitude of sesmic events proportional to the amplitude of the SP event with value of the correlation coefficient between the both is more than 80.0%, the seismic events caused the material in its path have excessive pressure that pore fluid in the material move and cause the separation of charge is the source of the appear of SP signal, the greater the amplitude of the seismic event the pressure exerted on the material so that the larger the amplitude of the SP events formed also getting bigger, this is in accordance with the theory of the seismoelectric phenomenon by electrokinetic effect mechanismKeyword: Bledug Kuwu, Self Potential (SP), seismic, dominant frequency, different arrival time, amplitude and seismoelectric effect.
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Wu, Jing, Li Wu, Miao Sun, Ya-ni Lu i Yan-hua Han. "Application of Boundary Local Feature Scale Adaptive Matching Extension EMD Endpoint Effect Suppression Method in Blasting Seismic Wave Signal Processing". Shock and Vibration 2021 (13.08.2021): 1–9. http://dx.doi.org/10.1155/2021/2804539.
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The intrinsic endpoint effect of empirical mode decomposition (EMD) will lead to serious divergence of the intrinsic mode function (IMF) at the endpoint, which will lead to the distortion of IMF and affect the decomposition accuracy of EMD. In view of this phenomenon, an EMD endpoint effect suppression method based on boundary local feature scale adaptive matching extension was proposed. This method can consider both the change trend of the signal at the endpoint and the change rule of the signal inside. The simulation results showed that the proposed method had better suppression effect on the intrinsic endpoint effect of EMD than the traditional EMD endpoint effect suppression method and achieved high-precision IMF. The endpoint effect suppression method of EMD based on boundary local feature scale adaptive matching extension was used to process the actual blasting seismic signal. The decomposition results showed that the method can effectively suppress the endpoint effect of EMD of blasting seismic signal and are helpful to extract the detailed characteristic parameters of blasting seismic signal.
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Zhao, Binghui, Liguo Han, Pan Zhang i Yuchen Yin. "Weak Signal Enhancement for Passive Seismic Data Reconstruction Based on Deep Learning". Remote Sensing 14, nr 21 (24.10.2022): 5318. http://dx.doi.org/10.3390/rs14215318.
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In conventional passive seismic exploration, it is often necessary to make a long-period seismic record. On the one hand, the passive seismic records with long period allowed us to screen several good passive seismic records with long period for seismic interferometry reconstruction and perform piecewise stacking on them. On the other hand, a sufficiently long recording time can help us avoid noise interference generated by nonpassive sources during the recording process, such as animal activities, construction operations, industrial electrical interference, etc. Compared with the passive seismic records with short period, the passive seismic records with long period can obtain higher signal-to-noise ratio after seismic interferometry reconstruction. However, they also cause huge consumptions of manpower, material resources, and time. Based on this, this paper proposes a seismic interferometry reconstruction method using passive signals of short-period recordings. Based on deep learning technology, the effective information is extracted and enhanced, the strong coherent noise after reconstruction is suppressed and weakened, the SNR of reconstructed recording is improved, and the effective information is mined. It can effectively reduce the time of passive seismic recording required for acquisition and improve acquisition efficiency. In addition, it also has a certain monitoring effect on real-time changes in underground structures.
Rozprawy doktorskie na temat "Seismic signal effect"
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Kuehnert, Julian. "Simulation of High Frequency Seismic Waves generated by Rockfalls on Real Topography". Thesis, Université de Paris (2019-....), 2019. https://theses.md.univ-paris-diderot.fr/KUEHNERT_Julian_va2.pdf.
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Les risques d'éboulements doivent être évalués et surveillés afin de prévenir les pertes de vies humaines et dommages aux infrastructures. A cet égard, il est important de créer des catalogues d'événements et de comprendre la dynamique des éboulements. Les ondes sismiques peuvent être utiles à cette fin, car elles transmettent des informations précieuses sur l'événement. Elles sont générées lorsque des éboulements touchent le sol et peuvent être utilisées pour détecter, classer et localiser des événements. Plus encore, on peut déduire des propriétés des éboulements telles que leur volumes et leur comportement dynamique. Cependant, les signaux sismiques hautes fréquences (>1Hz) sont mal compris. En effet, ils sont associés à des sources sismiques complexes qui sont réparties dans l'espace et peuvent varier rapidement dans le temps. De plus, les ondes sismiques hautes fréquences sont susceptibles d'être diffusées et diffractées en raison des interactions avec les hétérogénéités du sol ou la topographie de surface. Cette thèse franchit une étape importante dans la compréhension des signaux sismiques hautes fré-quences des éboulements en simulant la propagation des ondes sismiques en utilisant la méthode des éléments spectraux (SEM) avec des profils de vitesse réalistes et des topographies de surface 3D. L'influence de la topographie sur le champ des ondes sismiques est étudiée. On constate que l'ampli-fication induite par la topographie est sensiblement différente entre les sources situées en profondeurs et celles situées en surface. En effet, les ondes de surface générées par des sources peu profondes sont exposées à une diffusion et à une diffraction constantes lorsqu'elles se déplacent le long de la surface. La désintégration de l'énergie le long de la surface est étudiée pour différents modèles de vitesse et des équations sont dérivées pour calculer rétroactivement l'énergie sismique totale rayonnée par la source. Ceci est intéressant du fait du lien entre l'énergie sismique et le volume d'éboulement. Afin de tenir compte des effets topographiques, il est proposé un facteur de correction qui peut être introduit dans le calcul de l'énergie. Les signaux sismiques générés par les éboulements du cratère Dolomieu du Piton de la Fournaise, à La Réunion, sont analysés. Les sismogrammes synthétiques sont utilisés pour identifier et interpréter les signaux observés qui sont générés par des impacts uniques. L'influence de la topographie sur les formes d'onde est démontrée et la sensibilité avec l'emplacement et la direction de la source est évaluée. Les caractéristiques du signal telles que les amplitudes et le contenu fréquentiel sont expliquées sur la base de la théorie du contact de Hertz. De plus, les rapports spectraux entre stations, calculés à partir des signaux sismiques d'éboulement, sont considérés comme caractéristiques de la position de la source. La comparaison avec les rapports spectraux simulés suggère qu'ils sont dominés par la propagation le long de la topographie plutôt que par le mécanisme de la source. Sur la base de ces résultats, une méthode est proposée pour la localisation des éboulements à l'aide de rapports énergétiques simulés entre stations. La méthode est appliquée pour localiser les éboulements dans le cratère de Dolomieu. La mise en œuvre de la méthode implique une fenêtre temporelle glissante qui permet une application simple sur des signaux sismiques continus. L'accent est mis sur la capacité de la méthode à surveiller l'activité des éboulements en temps réelRockfall hazard has to be evaluated and monitored in order to prevent loss of life and infrastructure. In this regard it is important to create event catalogs and understand rockfall dynamics. Seismic waves can help for this purpose as they carry valuable information of the event. They are generated when rockfalls impact the ground and can be used to detect, classify and locate events. Beyond that, rockfall properties such as their volume and their dynamic behavior can be inferred. Yet, high frequency seismic signals (>1Hz) are poorly understood. This is because they are associated to complex seismic sources which are spatially distributed and can rapidly vary over time. On top of this, high frequency seismic waves are prone to be scattered and diffracted due to interactions with soil heterogeneities or surface topography. This thesis takes an important step forward to enhance understanding of high frequency rockfall seismic signals by simulating seismic wave propagation on domains with realistic velocity profiles and 3D surface topographies using the Spectral Element Method (SEM). The influence of the topography on the seismic wave field is investigated. It is found that topography induced amplification is substantially different between deep sources and sources located at the surface. This is because surface waves generated by shallow sources are exposed to constant scattering and diffraction when traveling along the surface. The energy decay along the surface is investigated for different velocity models and equations are derived to back-calculate the total seismic energy radiated by the source. This is of interest as the rockfall seismic energy is related to the rockfall volume. In order to account for topography effects, a correction factor is proposed which can be introduced in the energy calculation. Observed seismic signals generated by rockfall at Dolomieu crater on Piton de la Fournaise volcano, La Réunion, are analyzed. Synthetic seismograms are used to identify and interpret observed signals generated by single impacts. The influence of topography on the waveforms is demonstrated and the sensitivity on source location as well as source direction is evaluated. Signal characteristics such as amplitudes and frequency content are explained based on Hertz contact theory. Additionally, inter-station spectral ratios computed from rockfall seismic signals are shown to be characteristic of the source position. Comparison with simulated spectral ratios suggest that they are dominated by the propagation along the topography rather than the mechanism of the source. Based on these findings, a method is proposed for the localization of rockfalls using simulated inter-station energy ratios. The method is applied to localize rockfalls at Dolomieu crater. The implementation of the method involves a sliding time window which allows a straightforward application on continuous seismic signals. The potential of the method to monitor rockfall activity in real-time is emphasized
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Karthikeyan, E. "Studies of system identification and denoising for geophysical signals". Thesis, 2018. http://eprint.iitd.ac.in:80//handle/2074/7928.
Pełny tekst źródłaKsiążki na temat "Seismic signal effect"
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Wiszniowski, Jan. Broadband seismic system: Effect of transfer band on detection and recording of seismic waves. Warszawa: Polish Academy of Sciences, Institute of Geophysics, 2000.
Znajdź pełny tekst źródłaCzęści książek na temat "Seismic signal effect"
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Berrino, Giovanna, i Umberto Riccardi. "Far-field Gravity and Tilt Signals by Large Earthquakes: Real or Instrumental Effects?" W Geodetic and Geophysical Effects Associated with Seismic and Volcanic Hazards, 1379–97. Basel: Birkhäuser Basel, 2004. http://dx.doi.org/10.1007/978-3-0348-7897-5_6.
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Varotsos, Panayiotis A., Nicholas V. Sarlis i Efthimios S. Skordas. "Natural Time Investigation of the Effect of Significant Data Loss on Identifying Seismic Electric Signals". W Natural Time Analysis: The New View of Time, 237–45. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-16449-1_5.
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Harada, Makoto, Katsumi Hattori i Nobuhiro Isezaki. "Signal Discrimination of External Geomagnetic Effects Using the Transfer Function Approach with Continuous Wavelet Transform". W Handbook of Geophysical Exploration: Seismic Exploration, 243–58. Elsevier, 2010. http://dx.doi.org/10.1016/s0950-1401(10)04019-x.
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Erik Sjöberg, Lars, i Majid Abrehdary. "On Moho Determination by the Vening Meinesz-Moritz Technique". W Geodetic Sciences - Theory, Applications and Recent Developments [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97449.
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This chapter describes a theory and application of satellite gravity and altimetry data for determining Moho constituents (i.e. Moho depth and density contrast) with support from a seismic Moho model in a least-squares adjustment. It presents and applies the Vening Meinesz-Moritz gravimetric-isostatic model in recovering the global Moho features. Internal and external uncertainty estimates are also determined. Special emphasis is devoted to presenting methods for eliminating the so-called non-isostatic effects, i.e. the gravimetric signals from the Earth both below the crust and from partly unknown density variations in the crust and effects due to delayed Glacial Isostatic Adjustment as well as for capturing Moho features not related with isostatic balance. The global means of the computed Moho depths and density contrasts are 23.8±0.05 km and 340.5 ± 0.37 kg/m3, respectively. The two Moho features vary between 7.6 and 70.3 km as well as between 21.0 and 650.0 kg/m3. Validation checks were performed for our modeled crustal depths using a recently published seismic model, yielding an RMS difference of 4 km.
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García, Silvia, Paulina Trejo i Alberto García. "Intelligent VR-AR for Natural Disasters Management". W Augmented Reality [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99337.
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Considering the significance of improving natural disasters emergency management and recognizing that catastrophe scenes are almost impossible to reconstruct in real life, forcing persons to experience real hazards violates both law and morality, in this research is presented an engine for Virtual Reality/Augmented Reality (VR/AR) that works enhancing human capacities for prevention, response and recovery of natural phenomena effects. The selected novel techniques have very advantageous qualities to overcome the inconveniences detected in the most recent seismic devastating experience in Mexico City, the Sept 19th, 2017, earthquake M7.2: total collapse of more than 230 buildings, partial fall of 7 000 houses, 370 people were killed, and over 6,000 were injured. VR and AR provide researchers, government authorities and rescue teams with tools for recreating the emergencies entirely through computer-generated signals of sight, sound, and touch, when using VR, and overlays of sensory signals for experiences a rich juxtaposition of virtual and real worlds simultaneously, when AR is applied. The gap between knowledge and action is filled with visual, aural, and kinesthetic immersive experiences that poses a possibility to attend to the population in danger in a deeply efficient way, never experimented before.
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Giustiniani, Michela, i Umberta Tinivella. "Gas Hydrates in Antarctica". W Glaciers and Polar Environment [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94306.
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Few potential distributing areas of gas hydrates have been recognized in literature in Antarctica: the South Shetland continental margin, the Weddell Sea, the Ross Sea continental margin and the Wilkes Land continental margin. The most studied part of Antarctica from gas hydrate point of view is the South Shetland margin, where an important gas hydrate reservoir was well studied with the main purpose to determine the relationship between hydrate stability and environment effects, including climate change. In fact, the climate signals are particularly amplified in transition zones such as the peri-Antarctic regions, suggesting that the monitoring of hydrate system is desirable in order to detect potential hydrate dissociation as predicted by recent modeling offshore Antarctic Peninsula. The main seismic indicator of the gas hydrate presence, the bottom simulating reflector, was recorded in few parts of Antarctica, but in some cases it was associated to opal A/CT transition. The other areas need further studies and measurements in order to confirm or refuse the gas hydrate presence.
Streszczenia konferencji na temat "Seismic signal effect"
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D. Stefania, L. "Effect of phase variations of the signal to noise ratio of seismic data/ seismic modelling". W 70th EAGE Conference and Exhibition - Workshops and Fieldtrips. European Association of Geoscientists & Engineers, 2008. http://dx.doi.org/10.3997/2214-4609.20148095.
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Lei, Shao, Shen Fang, Linlin Xu, Chengzhi Jiang, Hongli Liu i Fuxiang Huang. "Signal Processing System for Seismic Exploration Based on Laser Doppler Effect". W 2006 8th international Conference on Signal Processing. IEEE, 2006. http://dx.doi.org/10.1109/icosp.2006.345496.
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Paraschivoiu, C. "The Effect of Irregular Spacing on the Signal-to-noise Ratio of Deep Seismic Reflection Data". W 77th EAGE Conference and Exhibition 2015. Netherlands: EAGE Publications BV, 2015. http://dx.doi.org/10.3997/2214-4609.201412523.
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Li, Bing, i D. K. Vijay. "Study of the Effect of FRS and SAM on Pipe Seismic Stress Using Taguchi Method". W ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77020.
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In this paper, the effect of floor response spectra (FRS) and seismic anchor movement (SAM) on the seismic stresses in the piping system is studied through a combination of finite element analysis (FEA) and the Taguchi Method. Class 3 piping systems according to ASME B&PV code Section III Subsection ND with different natural frequencies are analyzed in this study. Taguchi method is applied to create an orthogonal array to show the variability of FRS and SAM, which is taken as the ±20% variation over its nominal value. Based on the Taguchi orthogonal array, finite element simulations are carried out to obtain the seismic code stress in each piping system. From the Taguchi signal-to-noise (S/N) ratio analysis and the analysis of variance (ANOVA) of the seismic code stress results, the effect of FRS and SAM on the resultant seismic stress is given and expressed as a percentage. The study shows that the FRS is dominating the seismic stress for the piping system with low natural frequency (i.e., flexible system) while SAM is dominating the seismic stress for the piping system with high natural frequency (i.e., rigid system), for the piping system with a medium natural frequency, both FRS and SAM contribute to the seismic stress and the percentage of contribution of each parameter varies with the level of the system natural frequency. The results of this study also show that if the piping system is designed either too rigid or too flexible for the same layout, it will result in high resultant (primary plus secondary) seismic stress.
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Liang, Li, Pan Rong, Ren Guopeng i Zhu Xiuyun. "Research on Earthquake Acceleration Alarm of Nuclear Power Plant". W 2021 28th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/icone28-64554.
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Abstract Almost all nuclear power plants in the world are equipped with seismic instrument system, especially the third generation nuclear power plants in China. When the ground motion measured by four time history accelerometers of containment foundation exceeds the preset threshold, the automatic shutdown trigger signal will be generated. However, from the seismic acceleration characteristics, isolated and prominent single high frequency will be generated the acceleration peak, which has no decisive effect on the seismic response, may cause false alarm, which has a certain impact on the smooth operation of nuclear power plant. According to the principle of three elements of ground motion, this paper puts forward a method that first selects the filtering frequency band which accords with the structural characteristics of nuclear power plants, then synthesizes the three axial acceleration time history, and finally selects the appropriate acceleration peak value for threshold alarm. The results show that the seismic acceleration results obtained by this method can well represent the actual magnitude of acceleration, and can solve the problem of false alarm due to the randomness of single seismic wave, and can be used for automatic reactor shutdown trigger signal of seismic acceleration.
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Xiao, Xiu, Qingzi Zhu, Guanyi Wang, Shao-Wen Chen, Mamoru Ishii i Yajun Zhang. "Vibration Effects on Bubbly Flow Structure in an Annulus". W 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60735.
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In order to investigate the seismic vibration effect on two-phase flow structure, experiments were performed for upwards bubbly flow in an annulus channel with and without externally-induced vibration. The inner and outer diameters of the annulus are 19.1 mm and 38.1 mm respectively, and the total height of the test section is 2.32 m. To simulate seismic vibrations, the test section is attached to an eccentric cam vibration module with an eccentricity of 9.5 mm. The eccentric cam rotation speed can reach up to 210 rpm. Local two-phase flow parameters were measured along radial direction within the annulus gap using miniaturized four-sensor conductivity probe at axial location of z/Dh = 77. The semi-instantaneous local parameters at different vibration angles were analyzed by tracing the quasi-sinusoidal acceleration signal under vibration conditions. The results showed that the seismic vibration can significantly affect the local parameters in bubbly flow regime. Void fraction can increase by 10% compared with non-vibration condition. During the vibration cycle, the void fraction also changed greatly, especially in the near wall region. The interfacial area concentration (IAC) and Sauter mean diameter displayed the same behavior as the respective void fraction profiles.
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Tiwari, Pankaj Kumar, Debasis Priyadarshan Das, Parimal Arjun Patil, Prasanna Chidambaram, Prasanna Kumar Chandran, Raj Deo Tewari i M. Khaidhir Abdul Hamid. "4D Seismic in Subsurface CO2 Plume Monitoring – Why It Matters?" W SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206162-ms.
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Abstract CO2 sequestration in depleted carbonate reservoir stipulate incorporation of comprehensive and trailblazing monitoring technologies. 4D time-lapse seismic is sine qua non for Monitoring, Measurement and Verification (MMV) planning to demonstrate the migration of CO2 plume within geological storage. An ingenious, adaptive and site specific MMV plan for monitoring CO2 plume is paramount to minimize possible subsurface and project integrity risks. Integration of dynamic simulation with seismic forward modeling aggrandize the capabilities of 4D seismic in CO2 sequestration projects. Depleted carbonate reservoir has been thoroughly studied and its geomechanical and geochemical modeling results were coupled into dynamic simulation. Reservoir porosity and fluid properties along with CO2 saturation and injection pressure distribution within each reservoir level were generated. The dynamic simulation results were integrated with seismic forward modeling to demonstrate the CO2 plume migration and its impact on seismic amplitude. Fluid acoustic properties were computed for carbonate reservoir using FLAG method. Selection of wells was based on availability of superior quality acoustic logs as well as those representing the reservoir best. Gassmann fluid substitution exercise was carried using dry rock modeling. Several scenarios were generated, and results were analyzed to demonstrate the effect of CO2 saturation and pressure build-ups within reservoir on the seismic amplitude due to continuous CO2 injection. Synthetic seismic AVO gathers were generated for angles ranging from 5 to 50 degree. Near, Mid and Far seismic amplitude response at the top of carbonate reservoir were analyzed with respect to in-situ condition for each scenario. Results reveal that CO2 saturation as low as 25 - 30% in depleted carbonate reservoir can be distinguished from 4D time-lapse seismic. With continuous CO2 injection, the reservoir pressure increases and this in turn controls the properties of both in-situ and injected fluids. The gradual changes in fluid properties and their impact on bulk acoustic properties of reservoir were modeled to assess the feasibility of using 4D seismic as a predictive tool for detection of localized and provincial pressure build-ups. Modeling results show that although observed changes in amplitude on synthetic gathers were subtle, it is expected that 4D seismic with high signal-to-noise ratio possibly be able to image such localized pressure build-ups. To monitor CO2 plume migration as well as localized pressure build-ups, we recommend acquiring multi-azimuth (MAZ) surface seismic in combination with 3D DAS-VSP for superior subsurface imaging. The integrated modeling approach ensures that 4D Seismic in subsurface CO2 plume monitoring is robust. Monitoring pressure build-ups from MAZ surface seismic and 3D DAS-VSP will reduce the associated risks.
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Matsuoka, Taichi, Takuya Wada i Mizuki Katakura. "Vibration Suppression of Traffic Signal Pole by Generating Electrical Power". W ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-97351.
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The authors propose a damper that generates electrical power in order to not only suppress vibration and also get electrical energy when many traffic signal poles are oscillated by wind, traffic turbulence, and earthquake. The damper consists of a displacement magnifying mechanism by using levers, solenoid coils and rare-earth magnets. It is useful for small deformation between a beam and a column of the traffic pole. Vibration modes of the pole are analyzed by using FEM, and then a small scale model of the traffic pole is built up. The small scale model has 2.3 m high, consists of a steel column and a cantilever beam due to rescale about 1/3 of real scale one, and natural frequency is about 3.5 Hz. Trial damper is manufactured and a damping force, which is caused by the coils crossing magnetic field, is adjusted. Dynamic characteristics of the trial damper are measured by a shaking actuator. In order to confirm vibration reduction, both of seismic and harmonic vibration tests of small scale model when the trial damper is installed are carried out by using a shaking table. The experimental results of harmonic responses are compared with the calculated results by FEM, and effect of vibration suppression and efficiency of generating power are discussed experimentally and numerically.
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Silvestrov, Ilya, Emad Hemyari, Andrey Bakulin, Yi Luo, Ali Aldawood, Flavio Poletto, Yujin Liu, Yue Du, Anton Egorov i Pavel Golikov. "Processing of Seismic-While-Drilling Data from the DrillCAM System Acquired with Wireless Geophones, Top-Drive, and Downhole Vibrations Sensors". W SPE Middle East Oil & Gas Show and Conference. SPE, 2021. http://dx.doi.org/10.2118/204543-ms.
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Abstract We present processing details of seismic-while-drilling data recently acquired on one of the onshore wells by a prototype DrillCAM system with wireless geophones, top-drive, and downhole vibration sensors. The general flow follows an established practice and consists of correlation with a drillbit pilot signal, vertical stacking, and pilot deconvolution. This work's novelty is the usage of the memory-based near-bit sensor with a significant time drift reaching 30-40 minutes at the end of each drilling run. A data-driven automatic time alignment procedure is developed to accurately eliminate time drift error by utilizing the top-drive acceleration sensor as a reference. After the alignment, the processing flow can utilize the top-drive or the near-bit pilots similarly. We show each processing step's effect on the final data quality and discuss some implementation details.
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Szu, Harold. "Neural network adaptive wavelet transform". W OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oam.1992.fa3.
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Daughters { h a b ( t ) = h [ ( t − b ) / a ] / a } constructed by dilation aand shift bof a single mother wavelet h(t) form the basis of the wavelet transform (WT) coined by French geologists Morlet et al.in 1985. The physics behind the WT is a bank of matched filters1of a constant resonator Qfor seismic imaging. The condition to be a mother wavelet is to be zero-dc square integrable. Let the Fourier transform (FT) be the inner product: FT { e } = ( s , e ) = ∫ s ( t ) e ( t ) d t , with e(t) = exp(2πjft). Then a windowed FT becomes the Gabor GT{s} = (s,g), where g(t) = exp[−(t/τ)2]exp(2πjft), and Morlet's WT{s} = (s,gab), where g a b ( t ) = g [ ( t − b ) / a ] / a . Applications are based either on an efficient, faithful, noise-immune wide band transient representation or on a sensitive, robust, truthful signal classsification. While the former optimizes the majority signals' energy, the latter works on the overlapping boundary and outliers. A superset of mother wave lets is introduced for adaptive WT using neural nets to explain the cocktail party hearing effect.
Raporty organizacyjne na temat "Seismic signal effect"
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Taylor, Oliver-Denzil, Amy Cunningham,, Robert Walker, Mihan McKenna, Kathryn Martin i Pamela Kinnebrew. The behaviour of near-surface soils through ultrasonic near-surface inundation testing. Engineer Research and Development Center (U.S.), wrzesień 2021. http://dx.doi.org/10.21079/11681/41826.
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Seismometers installed within the upper metre of the subsurface can experience significant variability in signal propagation and attenuation properties of observed arrivals due to meteorological events. For example, during rain events, both the time and frequency representations of observed seismic waveforms can be significantly altered, complicating potential automatic signal processing efforts. Historically, a lack of laboratory equipment to explicitly investigate the effects of active inundation on seismic wave properties in the near surface prevented recreation of the observed phenomena in a controlled environment. Presented herein is a new flow chamber designed specifically for near-surface seismic wave/fluid flow interaction phenomenology research, the ultrasonic near-surface inundation testing device and new vp-saturation and vs-saturation relationships due to the effects of matric suction on the soil fabric.