Removal of scattered surface waves using multicomponent seismic data

Geophysics ◽  
1996 ◽  
Vol 61 (5) ◽  
pp. 1483-1488 ◽  
Author(s):  
Bastian Blonk ◽  
Gérard C. Herman
Keyword(s):  
Surface Waves ◽  
Seismic Data ◽  
Body Wave ◽  
Simulated Data ◽  
Inverse Scattering Method ◽  
The Body ◽  
Scattering Method ◽  
Wave Reflections ◽  
Shallow Subsurface

In many exploration areas, the shallow subsurface is strongly heterogeneous. The heterogeneities can give rise to scattering of surface waves. These scattered waves can depreciate the quality of land seismic data when they mask the body‐wave reflections from the deeper part of the subsurface. Surface waves scattered near a line of receivers (inline‐scattered waves) can be removed by well‐known filtering techniques (see e.g., Yilmaz, 1987, section 1.6.2). However, surface waves scattered far from the receiver line (crossline‐scattered waves) are left intact partially by filtering because these waves can resemble body‐wave reflections. In previous papers, we have discussed an inverse scattering method for removing scattered surface waves from simulated data (Blonk and Herman, 1994), as well as from field data (Blonk et al., 1995). So far, we have limited our attention to the vertical components of the particle velocity which implies that surface waves and body‐wave reflections can be distinguished on the basis of their respective differences in phase velocity.

An elastodynamic inverse scattering method for removing scattered surface waves from field data

Geophysics ◽  
1995 ◽  
Vol 60 (6) ◽  
pp. 1897-1905 ◽  
Author(s):  
Bastian Blonk ◽  
Gerard C. Herman ◽  
Guy G. Drijkoningen
Keyword(s):  
Surface Waves ◽  
Inverse Scattering ◽  
Seismic Data ◽  
Field Data ◽  
Inverse Scattering Method ◽  
Scattering Method ◽  
Data Sets ◽  
Propagation Characteristics ◽  
Fitting Procedure ◽  
Separate Source

In an earlier paper, we introduced a 3-D inverse scattering method for removing scattered surface waves from seismic data that was based on a tomographic imaging of the scattered surface waves by a data‐fitting procedure that used as much of the seismic data as possible. After this imaging step, the scattered surface waves can be computed and removed for each separate source‐receiver pair. We now apply the method to two field‐data sets. The method requires a knowledge of the source waveform and shallow propagation characteristics, and these input requirements are estimated from the direct surface wave. We conclude that the method effectively attenuates crossline scattered surface waves without affecting deeper reflections.

Surface waves in structures with locally irregular boundaries

1980 ◽  
Vol 70 (3) ◽  
pp. 791-808
Author(s):  
Anne Suteau ◽  
Louis Martel
Keyword(s):  
Surface Waves ◽  
Body Wave ◽  
Complex Structure ◽  
Additional Term ◽  
The Body ◽  
Body Waves ◽  
First Order ◽  
Irregular Region ◽  
Regular Medium ◽  
General Method

abstract The transmitted field due to surface waves incident on a local irregularity of a plane-layered medium has been studied. A perturbation method to the first order and the Born approximation can be used if the variations in the thickness of the layers are sufficiently smooth and the wavelengths are long when compared to the size of the irregularities. The spectrum of the perturbed part of the displacement field at the surface is a sum over the surface-wave modes for the regular medium, with an additional term involving the scattered body waves. Numerical computations have been performed for structures composed of a layer overlying a half-space. The contribution of the various modes to the transmitted Love or Rayleigh fields has been studied for several structures. A general method has been obtained to analyze the effect of a complex structure as the superposition of the fields due to simpler ones. When the layer thickness is kept unchanged, the incident mode is not perturbed to the first order. Synthetic seismograms, computed at stations sufficiently close to the irregular region, show how the perturbation of the signal depends on distance. A comparison has been made for Love waves with a finite element method. Both methods give very similar results when the stations are not too close to the irregularities so that the body-wave contribution is negligible. The local phase velocity shows departures from the curves for a regular model.

scholarly journals Neural Network-Based Laser Interferometer Compensation for Seismic Signal Detection

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Kyunghyun Lee ◽  
Hyungkwan Kwon ◽  
Kwanho You
Keyword(s):  
Neural Network ◽  
Frequency Domain ◽  
Seismic Data ◽  
Seismic Waves ◽  
Laser Interferometer ◽  
Body Wave ◽  
Measurement Data ◽  
The Body ◽  
Fusion Algorithm ◽  
Heterodyne Laser Interferometer

We propose a seismic wave detection method in the frequency domain using a heterodyne laser interferometer, which is used in ultraprecision fields as a displacement measurement device. In seismology, it is important to accurately measure seismic waves. To overcome the limited frequency range and low resolution of accelerometers and velocimeters and to enhance the precision of seismic data analysis, we use the heterodyne laser interferometer as a seismic detection apparatus. We apply the data fusion algorithm with the adaptive standard deviation ratio (ς) derived from the neural network to improve the laser interferometer’s measurement precision. Moreover, by using the interferometric characteristics, we analyze the seismic data in the frequency domain. To determine the location of the epicenter from the body wave propagation analysis, we apply the STA/LTA algorithm to the measurement data. The effectiveness of the proposed laser interferometric seismometer is shown through experiments to locate the precise epicenter.

scholarly journals Seismic Characterization of the Nevada National Security Site Using Joint Body Wave, Surface Wave, and Gravity Inversion

2019 ◽  
Vol 110 (1) ◽  
pp. 110-126
Author(s):  
Leiph Preston ◽  
Christian Poppeliers ◽  
David J. Schodt
Keyword(s):  
Surface Wave ◽  
National Security ◽  
Surface Waves ◽  
Body Wave ◽  
Wave Dispersion ◽  
The Body ◽  
Body Waves ◽  
Gravity Inversion ◽  
Surface Wave Dispersion ◽  
Near Surface

ABSTRACT As a part of the series of Source Physics Experiments (SPE) conducted on the Nevada National Security Site in southern Nevada, we have developed a local-to-regional scale seismic velocity model of the site and surrounding area. Accurate earth models are critical for modeling sources like the SPE to investigate the role of earth structure on the propagation and scattering of seismic waves. We combine seismic body waves, surface waves, and gravity data in a joint inversion procedure to solve for the optimal 3D seismic compressional and shear-wave velocity structures and earthquake locations subject to model smoothness constraints. Earthquakes, which are relocated as part of the inversion, provide P- and S-body-wave absolute and differential travel times. Active source experiments in the region augment this dataset with P-body-wave absolute times and surface-wave dispersion data. Dense ground-based gravity observations and surface-wave dispersion derived from ambient noise in the region fill in many areas where body-wave data are sparse. In general, the top 1–2 km of the surface is relatively poorly sampled by the body waves alone. However, the addition of gravity and surface waves to the body-wave dataset greatly enhances structural resolvability in the near surface. We discuss the methodology we developed for simultaneous inversion of these disparate data types and briefly describe results of the inversion in the context of previous work in the region.

scholarly journals Interferometric surface-wave isolation and removal

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. A69-A73 ◽  
Author(s):  
David F. Halliday ◽  
Andrew Curtis ◽  
Johan O. A. Robertsson ◽  
Dirk-Jan van Manen
Keyword(s):  
Surface Wave ◽  
Data Quality ◽  
Surface Waves ◽  
Survey Data ◽  
Seismic Data ◽  
Body Wave ◽  
Seismic Survey ◽  
Seismic Interferometry ◽  
Wave Component ◽  
Ground Roll

The removal of surface waves (ground roll) from land seismic data is critical in seismic processing because these waves tend to mask informative body-wave arrivals. Removal becomes difficult when surface waves are scattered, and data quality is often impaired. We apply a method of seismic interferometry, using both sources and receivers at the surface, to estimate the surface-wave component of the Green’s function between any two points. These estimates are subtracted adaptively from seismic survey data, providing a new method of ground-roll removal that is not limited to nonscattering regions.

Experience in the use of double broncholytic therapy in occupational practice

2019 ◽  
pp. 303-307
Author(s):  
Elena A. Beigel ◽  
Natalya G. Kuptsova ◽  
Elena V. Katamanova ◽  
Oksana V. Ushakova ◽  
Oleg L. Lakhman
Keyword(s):  
Quality Of Life ◽  
Personal Data ◽  
The Body ◽  
Step Test ◽  
Aluminum Production ◽  
Chronic Obstructive ◽  
Body Plethysmography ◽  
Occupational Copd ◽  
The Impact

Introduction. Occupational chronic obstructive pulmonary disease (COPD) is one of the leading nosological forms of occupational respiratory disease. Numerous studies have shown high effectiveness of the combination of indacaterol/glycopyrronium (Ultibro®breezhaler®) on the impact on clinical and functional indicators in the treatment of COPD in General practice.The aim of the investigation the case of occupational COPD with the analysis of the dynamics of functional indicators, tolerance to physical load and evaluation of the quality of life of workers engaged in aluminum production by using combination of indacaterol/glycopyrronium.Materials and methods. The random sampling method included 20 men, workers of aluminum production, with the established diagnosis of professional COPD at the age of 40 to 60 years. The survey was conducted (Borg scale, medical Research Council scale (mMRC) and COPD Assessment Test (CAT). Functional methods of studies were conducted: spirometry, body plethysmography, electrocardiography (ECG) and the six-minute stepper test (6-MST).Results. Against the background of 8 weeks of therapy, the volume of forced exhalation for 1 minute (FEV1) increased by 14.7% and amounted to 67.90% of the due values, the forced vital capacity of the lungs (FVC) increased by 11.3% and amounted to 76.95% of the due. According to the body plethysmography (BPG) is set to decrease in residual lung volume on average by 13.4% and static hyperinflation, confirmed by the decrease in functional residual volume (FRV) of 18.8%. During the study period increased physical activity of patients. The average difference between the distance traveled in the six-minute step test before and after treatment was 58.8 m. The analysis of personal data showed that the quality of life of patients improved, the total score in the questionnaire CAT at the beginning of the study was 16.9 points, and after 8 weeks decreased by 63% and amounted to 10.7 points.Conclusions: The Results indicate a positive effect of combination therapy with indacaterol/glycopyrronium on the course and progression of occupational COPD.

PENGARUH KONSEP DIRI DAN KOMPETENSI PEDAGOGIK GURU TERHADAP KUALITAS PROSES PEMBELAJARAN

Edum Journal ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 106-117
Author(s):  
Khamim Khamim ◽  
Wresni Pujiyati
Keyword(s):  
Significant Influence ◽  
Learning Process ◽  
The Body ◽  
Self Concept ◽  
Survey Method ◽  
Empirical Level ◽  
Pedagogical Competence ◽  
Teacher Needs ◽  
Evaluation Of Learning

The main focus of this research is on the self-concept and pedagogical competence of the teacher and its influence on the quality of the learning process both partially and double. The research method used is a survey method in which the authors go directly to the empirical level by distributing questionnaires to 47 teachers. The processing and analysis techniques used are linear and multiple regression. The results of the study show that: (1) There is a positive and significant influence of the teacher's self-concept on the quality of the learning process (2) There is a positive and significant influence on the teacher's pedagogical competence on the quality of the learning process. (3) There is a positive and significant effect of self-concept and pedagogical competence of teachers together on the quality of the learning process. Therefore, the authors suggest: (1) So that the teacher improves health and appearance because the results of the study show that the weakness of the teacher's self-concept is in the appearance and significance of the body. So that the teacher needs to be given enlightenment related to how to maintain health and fitness through the implementation of joint gymnastics or conducting group discussions related to the dirt to maintain a prime body. (2) To face future competition and improve the quality of education it is deemed necessary to further increase the pedagogical competence of teachers, especially those related to planning and evaluation of learning.

February 9 — Dentist Day in Russia

2020 ◽  
pp. 78-81
Author(s):  
Oksana Rybachok
Keyword(s):  
Early Childhood ◽  
Oral Cavity ◽  
Salivary Glands ◽  
Spiritual Development ◽  
The Body ◽  
Mechanical Processing ◽  
Normal Functioning ◽  
Digestion Process ◽  
Quality Of Food

«Man is what he eats,» these words belong to the great Pythagoras. He meant by these words the connection of the origin of consumed food with the spiritual development of man. In fact, a lot depends on the nature of nutrition, the quality of food and, of course, on the degree of its perception by the body. Digestion process begins not in the stomach, but directly in the oral cavity as a result of mechanical processing of products with teeth and under the influence of the secretion of the salivary glands. That is why healthy teeth are the key to the normal functioning of the whole organism — people should start taking care of their teeth from the early childhood and dentists, who are far from being beloved by everybody and are often carelessly evaded, are called upon to help keep the teeth healthy.

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