Interference Of Surface Waves Research Articles

A shared-aperture pentaband antenna with high impedance surface for CubeSat application

A circular polarized (CP) pentaband antenna based on the aperture-in-aperture (AIA) concept is presented for CubeSat applications. This AIA consists of five different bands ranging from L-band to Ka-band. Four different antennas, each operating at a specific frequency band, namely 12 GHz, 18.5 GHz, 26 GHz, and 32 GHz, were incorporated into an L-band (viz. 1.5 GHz) antenna. Notably, the five antennas can operate simultaneously for a CubeSat downlink operation with a frequency ratio of 21.3:1. The antenna structure shows a realized gain of 5–10 dBi with good CP bandwidth (< 3 dB) across the overall operational frequency range. That is, the realized gain of L-band (1.5 GHz), X-band (12.5 GHz), K-band1 (18.5 GHz), K-band2 (26 GHz), and Ka-bands (32 GHz) are 5.05 dBi, 8.21 dBi, 7.33 dBi, 7.97 dBi, and 8.56 dBi. A high impedance surface (HIS) is incorporated with the Ka-band antenna to mitigate the ripples in the radiation pattern created by the interference of surface waves. A prototype was fabricated and tested. The measurement data agrees well with the simulation.

Exploring the Influence of Seismic Source and Improvement Methods on Tunnel Seismic Prediction

Abstract Tunnel seismic advanced prediction method is essential for detecting abnormal bodies ahead of the tunnel face and minimizing risks during tunnel construction. Selecting the seismic source plays a crucial role in influencing the precision and effectiveness of data acquisition. At present, tunnel seismic data is usually collected using explosive and sledgehammer sources. Nevertheless, the various sources are located in different positions within the tunnel excavation zone, resulting in distinct characteristics observed on the surface and reflected waves in the acquired tunnel seismic data. The explosive source has minimal surface wave interference, but it is expensive. However, the sledgehammer source is economical yet plagued by inadequate energy and substantial surface wave disruption. Regrettably, there is a lack of research on seismic sources in tunnels, which impairs the precise interpretation of forecasting conclusions from these sources. This paper seeks to investigate how various sources impact tunnel seismic prediction and suggests a new method that integrates data acquisition and processing from these sources. The explosive source is used once, while the sledgehammer source is used 24 times. Cross-correlation calculations are conducted to enhance the resolution of sledgehammer source data, reducing surface wave interference, based on seismic data obtained from the explosive source. Extensive numerical simulations and tunnel experiments support the validity of this method, highlighting its potential to lower data acquisition expenses and enhance tunnel seismic prediction accuracy.

Algorithm for Surface Wave Suppression on 2D Seismic Data Using the Slant Karhunen–Loeve Transform in a Time-Frequency Domain

Abstract —Surface waves are the main source of coherent noise in land seismic survey, and their suppression is one of the main stages of common depth point data processing designed to improve the quality of tracking primary reflections on time sections. In practice, noise reduction is carried out using procedures from modern software based on numerical modeling of waveforms. However, they are too resource-intensive and have a large number of subjectively customizable parameters. The known algorithms have a common drawback: either the energy of reflected waves is distorted in an interference zone with a noise wave or the noise suppression quality is unsatisfactory. The current research is aimed at improving the filtering algorithm in a time-frequency domain using the slant Karhunen–Loeve transform in order to overcome these limitations, to increase the accuracy and rate of its software implementation, and also to test it when processing profile field data from land-based 2D seismic surveys. The algorithm is modified by developing a new method for determining static corrections for surface wave hodograph rectification in a time-frequency domain and by the application of preprocessing in which the reflected wave signal is removed preliminarily. These and other modifications ensure faster calculations and improve the quality of surface wave interference suppression. In addition, the slant Karhunen–Loeve transform is accelerated by parallelizing calculations across logical processor cores. In this paper, the algorithm is described in detail, its significant advantage over the standard methods of bandpass filtering and F–K filtering is shown, and the results of processing the field data obtained by the SWANA procedure (Geovation 2.0) and by the slant Karhunen–Loeve transform. The result obtained by the slant Karhunen–Loeve transform is superior to the SWANA procedure in terms of the surface wave filtering quality and has only four adjustable parameters (SWANA has 20 parameters)

Depth Effect of Rock-Breaking Seismic Source by Drilling Jumbo in Subsea Tunnel with the Drill and Blast Method and Its Application Prospects

The drilling source of a drilling jumbo contains a great amount of noise in the construction of a subsea tunnel, which leads to a large prediction error for the conventional source selection method. To address this problem, this paper proposes an optimization method for the source selection of a drilling jumbo. The optimal truth element is selected for the advanced prediction of a subsea tunnel to ensure the safety of the subsea tunnel construction. First, a spectrum analysis of borehole seismic sources with different drilling depths is carried out, the noise interference contained in the seismic source signal at different drilling depths is analyzed, and the propagation law of a borehole seismic wave field at different depths is studied. Second, the deconvolution-cross-correlation method is used to denoise and reconstruct the seismic records of borehole sources at different depths, and a clutter and signal-to-noise ratio analysis of the reconstructed seismic records is carried out. The principle of optimal selection of the pilot signal time window is established to suppress random noise and surface wave interference. Finally, based on the actual project, the proposed method is evaluated. The results show that when using the optimization method of drilling source interception proposed in this paper, when the drilling jumbo is drilled to the deepest place, the selection of the source signal stationary section for advanced geological prediction is the best. The prediction results are basically consistent with the actual excavation situation, verifying the feasibility and effectiveness of the method.

Multimode dispersion measurement of surface waves extracted by multicomponent ambient noise cross-correlation functions

SUMMARY Cross-correlation functions of ambient seismic noise sometimes show multimode characteristics of surface waves, especially in observations in sedimentary areas and ocean areas. Multimode dispersion curves are useful for improving the depth resolution of subsurface imaging; nevertheless, measuring the multimode dispersion curves is not easy. Multimode interference of surface waves makes the cross-correlation functions complicated even without lateral heterogeneity of the subsurface structure, and the complex waveforms may result in unphysical dispersion measurement. We developed a method to determine multimode phase velocity dispersion curves based on the fitting of the synthetic cross-spectra to observed ones. The phase velocity in the synthetic cross-spectra is modelled as the function of a 1-D velocity structure, which achieves the measurement of physically realizable dispersion curves. The 1-D structures do not necessarily represent the Earth structure directly but act as model parameters of the dispersion curves within station pairs. The cross-spectral fitting has two steps, that is, array-based and single-pair fittings. The first step estimates the amplitude of each surface wave mode and the reference 1-D structure from the cross-spectral data within an array. The second step estimates the pair-dependent dispersion curves from the cross-spectra of a single station pair using the modal amplitudes and the reference structure estimated by the first step. The dispersion measurement based on the cross-spectral fitting can work even at short distances where the multimode inference is significant in the time-domain cross-correlation functions. We applied this method to synthetic and field data in seafloor observations. The synthetic and field applications show that the simultaneous use of multicomponent cross-correlation functions is effective to determine multimode dispersion curves. The multimode phase velocity dispersion curves in the ocean area are estimated stably even though the signal-to-noise ratio of cross-correlation functions is not high. The pair-dependent multimode dispersion curves estimated by the present method can serve as robust input data for high-resolution surface wave tomography.

Suppression of surface waves in seismic data based on the search for the main components of the wave field in the frequency-time domain

Suppression of surface wave interference is a necessary step in the processing of land seismic data. Traditional methods, such as single-channel band-pass filtering and multi-channel FK filtering, often fail to separate the desired signal from interference. The proposed method of suppressing surface waves based on the analysis of the main components of the wave field in the time-frequency domain shows the best results. The method is based on the model of surface wave propagation in horizontally layered media, however, numerical experiments were carried out demonstrating the applicability of the method in horizontally heteronode three-dimensional media. A software package "PF Seism" has been developed and registered, which implements the proposed method for suppressing surface waves.

Ground-roll extraction using the Karhunen-Loeve transform in the time-frequency domain

Ground-roll suppression is critical for seismic reflection data processing. Many standard methods, i.e., f-k fan filtering, fail when spatially aliased surface wave interference is present in the data. Spatial aliasing is a common problem; receiver spacing is often not dense enough to extract wavenumbers of low-velocity surface waves. It has long been known that the Karhunen-Loeve (KL) transform can be used to suppress aliased ground roll. However, the ground roll should be flattened before suppression, which is challenging due to the dispersion of surface wave velocities. I propose to solve this problem via the time-frequency domain. I apply the S-transform, which was previously shown to perform well in the multichannel analysis of surface waves. A simple complex-valued constant phase shift is a suitable model of surface wave propagation in common-frequency S-transform gathers. Therefore, it is easy to flatten the corresponding S-transform narrow-band frequency surface wave packet and extract it from the data by principal component analysis of the corresponding complex-valued data-covariance matrix. As the result, our S-transform KL (SKL) method filters the aliased ground roll without damaging the reflection amplitudes. The advantages of SKL filtering have been confirmed by synthetic- and field-data processing.

Ariyet Ocağında Kontrollü Patlatmalarla İlgili Bir Çalışma

Patlatma kaynaklı titreşimler çevre sakinlerini, tüm çevresel sorunlardan daha fazla endişelendirmektedir. Bina üst yapılarına verilen zararın patlatmadan kaynaklandığı iddia edilmektedir ve bazen bina sahibi, patlatma işlemlerini gerçekleştiren şirkete karşı dava açmaktadır. Patlatma kaynaklı titreşim problemi geçmişte kapsamlı bir şekilde araştırılmış ve devam eden araştırmalara konu olmaya devam etmektedir. Bu makale, bir otoyol prosesi kapsamında faaliyet gösteren taş ocağında yapılacak patlatmaların yüzeyden 9-10 m derindeki karstik kireçtaşlarına ve yeraltı sularına herhangi bir olumsuz etki etmemesi için gerekli çalışmaları içermektedir. Bu amaçla, titreşim ölçümü ve analizi yapılmış ve hedef bölgedeki patlatma kaynaklı yer titreşimlerini en aza indirgeyen yeni bir metodoloji uygulanmıştır. Patlatmanın neden olduğu zemin titreşiminin analizinde tepe partikül hızı ve baskın frekanslar dikkate alınmıştır. Metodoloji, hedef bölgedeki yüzey dalgalarının tahribatlı etkileşimini sağlamak için patlatma deliği gruplamaları arasında en uygun zaman gecikmelerini kullanmayı amaçlamaktadır.

3D-RVSP experimental study above a carbonate outcrop for coal resource exploration

In the areas where carbonate rocks expose to the near surface, there are several intractable issues in conventional surface seismic, including (1) weak reflection energy, (2) complex wave field and (3) serious static correction. Therefore, the seismic imaging result suffers significantly. However, RVSP is able to achieve reflected data with high quality since it generates seismic waves in borehole and receives seismic waves at the surface. In order to verify the applicability of RVSP technique in complex areas, this study carried out a 3D-RVSP seismic experiment in Wulunshan coal field, southwest China. Compared with the surface seismic data, RVSP data show higher signal-to-noise ratio, wider frequency band and weaker surface wave interference. In addition, two imaging methods (conventional CDP transform stack and novel equivalent-surface conversion) were implemented for RVSP data imaging. The imaging results show that the smaller and deeper structures can be revealed better by equivalent-surface conversion method than by CDP transform stack method. Hence, this study demonstrates that RVSP is an efficient method applied in the area with complex surface condition.

Polarization Filtering Method for Suppressing Surface Wave in Time-Frequency Domain

In order to suppress the surface wave in three-component seismic exploration, according to the polarization characteristics of body wave and surface wave, a time-frequency domain polarization filtering method based on wavelet transform was studied. A covariance matrix was constructed in the time-frequency domain for the three-component seismic data, measured the polarization parameters of seismic waves. Combining the corresponding eigenvalues and eigenvectors of the matrix, the elliptic rate and elevation angle were used as constraints, and the polarization filter function was built to separate the surface waves. The separated surface waves were inversely transformed and then were adaptively subtracted from the original records. After the polarization filtering suppressed the surface wave, the signal-to-noise ratio of the converted wave was effectively improved. It laid a good foundation for the next seismic data processing and seismic exploration development. The actual data processing results show that the method can effectively extract surface waves from three-component seismic records and avoid the interference of surface waves on seismic signals.

Subwavelength interference of light on structured surfaces

This paper presents a review of the subwavelength interference effects of light in structured surfaces. Starting from the anomalous interference in simple structures such as double nanoslits, thin films, and catenary apertures, the theories and applications of light–matter interaction in layered, periodic, and aperiodic subwavelength structures are discussed. Two basic platforms, i.e., Young’s double slits and the Fabry–Perot cavity, are used as prototypes for the investigation of the complex interference of surface waves. It is shown that these novel phenomena could dramatically reduce the characteristic lengths of functional devices and increase the resolution of optical imaging. By engineering the dispersion of surface waves, broadband responses beyond traditional limits in both temporal and spatial regimes have been demonstrated. As a final remark, the current challenges and future trends of subwavelength interference engineering are addressed.

New methodology to prevent blasting damages for shallow tunnel

From all of the environmental problems, blast-induced vibrations often cause concern to surrounding residents. It is often claimed that damage to building superstructures is due to blasting, and sometimes the building owner files a lawsuit against the company that perform blasting operations. The blast-vibration problem has been thoroughly investigated in the past and continues to be the subject of ongoing research. In this study, a tunnel construction has been performed by a construction company, according to their contract they must have used drilling & blasting method for excavation in tunnel inlet and outlet portal. The population is very condensed with almost tunnel below in the vicinity houses of one or two floors, typically built with stone masonry and concrete. This situation forces the company to take extreme precautions when they are designing blasts so that the blast effects, which are mainly vibration and aerial waves, do not disturb their surrounding neighbors. For this purpose, the vibration measurement and analysis have been carried out and a new methodology in minimizing the blast induced ground vibrations at the target location, was also applied. Peak particle velocity and dominant frequencies were taken into consideration in analyzing the blast-induced ground vibration. The methodology aims to employ the most suitable time delays among blast-hole groupings to render destructive interference of surface waves at the target location.

Analysis of the transient surface wave propagation in soft-solid elastic plates.

In dynamic elastography, the goal is to estimate the Young's modulus from audio-frequency wave propagation in soft-tissues. Within this frequency range, the shear wavelength is centimeter-sized while the compressional wavelength is meter-sized. Thus, the experimental data are usually collected in the near-field of the source. Near-field effects have been widely studied for bulk wave propagation. However, the near- and transient-fields of surface and guided waves have received less attention. In this work, the transient surface displacement field in soft-solid elastic plates in vacuum is analyzed. Due to the high Poisson's ratio, mode conversion has special characteristics in soft-solids. They are analyzed through this work where it is shown that the transient-field over the surface can be interpreted by tracing a few reflections. The authors show the existence of a critical distance needed for the formation of Rayleigh-Lamb modes. Below this distance, only direct surface waves propagate without contribution from reflected waves. Thus, the dispersion curve differs from that predicted by Rayleigh-Lamb modes. Instead, the authors propose a model based on the interference of surface waves, which agree with the experimental data. In addition, the conditions needed in order to retrieve the shear wave phase velocity from the surface field are given.

Role of the temperature dynamics in formation of nanopatterns upon single femtosecond laser pulses on gold

In this paper we investigate whether the periodic structures on metal surfaces exposed to single ultrashort laser pulses can appear due to an instability induced by two-temperature heating dynamics. The results of two-temperature model (TTM) 2D simulations are presented on the irradiation of gold by a single 800 nm femtosecond laser pulse whose intensity is modulated in order to reproduce a small initial temperature perturbation, which can arise from incoming and scattered surface wave interference. The growing (unstable) modes of the temperature distribution along the surface may be responsible for the LIPSS (Laser Induced Periodic Surface Structures) formation. After the end of the laser pulse and before the complete coupling between lattice and electrons occurs, the evolution of the amplitude of the subsequent modulation in the lattice temperature reveals different tendencies depending on the spatial period of the initial modulation. This instability-like behaviour is shown to arise due to the perturbation of the electronic temperature which relaxes slower for bigger spatial periods and thus imparts more significant modulations to the lattice temperature. Small spatial periods of the order of 100 nm and smaller experience stabilization and fast decay from the more efficient lateral heat diffusion which facilitates the relaxation of the electronic temperature amplitude due to in-depth diffusion. An analytical instability analysis of a simplified version of the TTM set of equations supports the lattice temperature modulation behaviour obtained in the simulations and reveals that in-depth diffusion length is a determining parameter in the dispersion relation of unstable modes. Finally it is discussed how the change in optical properties can intensify the modulation-related effects.

Numerical simulations of full-wave fields and analysis of channel wave characteristics in 3-D coal mine roadway models

Currently, numerical simulations of seismic channel waves for the advance detection of geological structures in coal mine roadways focus mainly on modeling twodimensional wave fields and therefore cannot accurately simulate three-dimensional (3-D) full-wave fields or seismic records in a full-space observation system. In this study, we use the first-order velocity–stress staggered-grid finite difference algorithm to simulate 3-D full-wave fields with P-wave sources in front of coal mine roadways. We determine the three components of velocity Vx, Vy, and Vz for the same node in 3-D staggered-grid finite difference models by calculating the average value of Vy, and Vz of the nodes around the same node. We ascertain the wave patterns and their propagation characteristics in both symmetrical and asymmetric coal mine roadway models. Our simulation results indicate that the Rayleigh channel wave is stronger than the Love channel wave in front of the roadway face. The reflected Rayleigh waves from the roadway face are concentrated in the coal seam, release less energy to the roof and floor, and propagate for a longer distance. There are surface waves and refraction head waves around the roadway. In the seismic records, the Rayleigh wave energy is stronger than that of the Love channel wave along coal walls of the roadway, and the interference of the head waves and surface waves with the Rayleigh channel wave is weaker than with the Love channel wave. It is thus difficult to identify the Love channel wave in the seismic records. Increasing the depth of the receivers in the coal walls can effectively weaken the interference of surface waves with the Rayleigh channel wave, but cannot weaken the interference of surface waves with the Love channel wave. Our research results also suggest that the Love channel wave, which is often used to detect geological structures in coal mine stopes, is not suitable for detecting geological structures in front of coal mine roadways. Instead, the Rayleigh channel wave can be used for the advance detection of geological structures in coal mine roadways.

3D mapping of elastic modulus using shear wave optical micro-elastography.

Elastography provides a powerful tool for histopathological identification and clinical diagnosis based on information from tissue stiffness. Benefiting from high resolution, three-dimensional (3D), and noninvasive optical coherence tomography (OCT), optical micro-elastography has the ability to determine elastic properties with a resolution of ~10 μm in a 3D specimen. The shear wave velocity measurement can be used to quantify the elastic modulus. However, in current methods, shear waves are measured near the surface with an interference of surface waves. In this study, we developed acoustic radiation force (ARF) orthogonal excitation optical coherence elastography (ARFOE-OCE) to visualize shear waves in 3D. This method uses acoustic force perpendicular to the OCT beam to excite shear waves in internal specimens and uses Doppler variance method to visualize shear wave propagation in 3D. The measured propagation of shear waves agrees well with the simulation results obtained from finite element analysis (FEA). Orthogonal acoustic excitation allows this method to measure the shear modulus in a deeper specimen which extends the elasticity measurement range beyond the OCT imaging depth. The results show that the ARFOE-OCE system has the ability to noninvasively determine the 3D elastic map.

Drill-rig noise suppression using the Karhunen-Loéve transform for seismic-while-drilling experiment at Brukunga, South Australia

Diamond-impregnated drill bits are known to be low energy vibration seismic sources. With the strong interference from the drill rig, it is difficult to obtain the drill-bit wavefield with a surface receiver array. To overcome the challenge of surface wave interference generated from the rig for seismic-while-drilling (SWD), we need to separate the rig- and bit-generated signals. To this end, we apply two wavefield separation methods, the Karhunen-Loéve (KL) transform and the f – k filter, and compare their performance. The applicability of these methods is based on the drill rig and drill bit having different spatial positions. While the drill-bit spatial position changes during the process of drilling, the drill rig remains stationary. This results in the source wavefields from the drill rig and the drill-bit having different characteristics, and allows us to separate and extract the drill-bit signal. We use a synthetic model to compare the KL transform and f – k filter. Both techniques are robust when the noise wavefield has consistent amplitude moveout. However, for changing amplitudes, such as the rig noise, which has an unrepeatable wavefield due to power amplitude variation, we show that the KL transform performs better in such situations. We also show the results of signal analysis of the SWD experiment data acquired from Brukunga, South Australia. We demonstrate the feasibility of the KL transform in separating the coherent noises from the stationary drill rig in a hard rock drilling environment, particularly emphasising the suppression of the surface and direct waves from the rig. The results show that drill-rig noise can be effectively suppressed in the correlation domain.

Surface plasmons at the Brillouin zone boundary of an oblique lattice

In periodic systems of low-symmetry, the Bragg condition for the complete interference of waves along the contour of the Brillouin zone (BZ) boundary is not generally satisfied. As a result, band-gaps do not necessarily occur at this boundary. This letter demonstrates this experimentally by recording the iso-frequency contours for surface plasmon polaritons (SPPs) supported on a diffraction grating with an underlying 2D oblique Bravias lattice. It is shown that these contours do not intersect the BZ boundary perpendicularly, as the symmetry operations of the lattice place no conditions on the surface wave interference at this boundary.

Marine fish diversity and habitat use along the western coast of the Black Sea

Event Abstract Back to Event Marine fish diversity and habitat use along the western coast of the Black Sea Viorel D. Gavril1, 2, 3* 1 Institutu of Biology, Bucharest, Romania 2 Oceanographic Research and Marine Environment Protection Society Oceanic-Club, Romania 3 University of Bucharest, Faculty of Geography, Romania Over the years the conditions of the Black Sea marine habitats have been modified due to anthropogenic impacts and climate change, and it is likely that the diversity of fish fauna changed as a result. This study provides new data regarding marine fish population diversity and habitat use along the western coast of the Black Sea. I recorded fish species and habitat data between 2011 and 2014 in two locations: Constanta, Romania and Shabla-Tyulenovo coast, Bulgaria, using fishing (only in Romania) and scuba visual transects (Romania and Bulgaria). During this period, we identified a number of 45 fish species, belonging to 14 orders and 30 families. Observations made while scuba diving were of great importance for this study, as 47% of the species were identified using this method. These species include Sciaena umbra, Salaria pavo, Coryphoblennius galerita, Callionymus pusillus, Aphia minuta, Ophidion rochei, Diplodus annularis, and Chelidonichthys lucerna. Five broad types of habitats were delimited for the species identified: pelagic, sandy bottoms, rocky bottoms, rocky habitats with Cystoseira sp. and man-made structures like breakwaters. Vertically, the delimitation was made above and below the 10 meter line based on due to the differences in temperature, light penetration and surface wave interference. I identified 34 species of fish in the Shabla-Tyulenovo area and 39 species in the Constanta area, of which 19 species preferred sandy bottoms, 21 rocky bottoms, 16 rocky habitats with Cystoseira sp., 19 man-made structures and 9 were pelagic. For 7 species habitat preferences could not be determined as a result of capture only by fishing. In conclusion, the scuba visual transects along with fishing methods provide a relevant image to the current state of the fish diversity along the western coast of the Black Sea. Acknowledgements I would like to acknowledge O.R.M.E.P.S. Oceanic-Club for supporting the costs for the participation to the XV European Congress of Ichthyology and providing logistic help during field work. This study was partially supported by the Romanian Academy, Institute of Biology, Bucharest Project 4 (RO1567-IBB04/2015). Keywords: Fishes, habitat use, Black Sea, Romania, SCUBA diving Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Oral Presentation Topic: Ecology, Conservation and Invasive Species Citation: Gavril VD (2015). Marine fish diversity and habitat use along the western coast of the Black Sea. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.FMARS.2015.03.00177 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Nov 2015; Published Online: 01 Dec 2015. * Correspondence: Mr. Viorel D Gavril, Institutu of Biology, Bucharest, Bucharest, Romania, viorel.gavril26@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract Supplemental Data The Authors in Frontiers Viorel D Gavril Google Viorel D Gavril Google Scholar Viorel D Gavril PubMed Viorel D Gavril Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Application of Three-Dimensional Seismic Exploration Technology in the Mining Area of Loess Plateau

Based on the first panel of some coal mine in the western loess tableland, this thesis has carried out three-dimensional exploration. The emphasis of experiment is shooting factor(well depth、dynamite), at the same time, the experiment of instrument factor and receiving factor has been carried out to choose the best shooting factor and receiving parameter. By proper layout observation system, elaborate static correction and comparison about various methods of static correction, this thesis has drawn the following conclusions: (1) From the experiment of well depth, interference wave is mainly composed of multiple refraction wave and surface wave, in general, the greater of the well depth, the smaller of the interference of refraction wave, and the interference of surface wave has dropped. Refraction wave energy is related to excitation horizons; (2)From receiving profile during the process of the experiment, the wave detector of dominant frequency being 25Hz has little difference with the wave detector of dominant frequency being 60Hz, so each has its advantages. The levels of reflection wave groups in coal seam of 60Hz profile are relatively abundant, and the continuity of the bottom reflection wave in coal seam of 60Hz profile is greater than 25Hz profile, and it is easier to trace, compare and explain. (3) From the process of the experiment, the complexity of surface conditions has little influence on data, on condition that being constructed strictly and completing static correction, it is absolutely possible to finish geological exploration.