Practical, yet critical, aspects of masw software are also discussed. To accomplish this task, the surface wave profiles at each location figure b. In fluid dynamics, dispersion of water waves generally refers to frequency dispersion, which means that waves of different wavelengths travel at different phase speeds. This can result in the combined activepassive analysis of surface waves for the purpose of obtaining both shallow e. Multichannel analysis of surface waves masw is a fast, lowcost, and environmentally friendly technique to estimate shear wave velocity profiles of soil sites. The backscattering analysis bsa algorithm incorporated in this software tries to enhance. May 03, 2012 masw multichannel analysis of surface wave in the radexpro seismic software.
For dispersion analysis, the phaseshift method by park et al. Dispersion analysis involved generation of dispersion image called overtone and extraction of dispersion curves from it. Easy masw is a new software for the interpretation and archiving of seismic data using the masw method multichannel analysis of surface waves. Back scattering of surface waves and how to utilize them are explained.
Analysis of dispersion and attenuation of surface waves in. The inversion uses the dispersion curve as the only empirical data with no reference to the original seismic record. Surfacewave analysis for estimating nearsurface properties khaled al dulaijan and robert r. Parkseis back scattering analysis bsa park seismic llc. Introduction seismic surface waves in an elastic halfspace propagating along the free surface were represented as the solution of equation of waves by lord rayleigh in 1885rayleigh, 18851. Top 10 papers on surface wave analysis for geotechnical. Arraybased measurements of surface wave dispersion and attenuation using frequencywavenumber analysis a thesis presented to the academic faculty by sungsoo yoon in partial fulfillment of the requirements for the degree doctor of philosophy in the school of civil and environmental engineering georgia institute of technology august 2005. More accurate near surface characterization provides the information between the upholes and a better static solution bottom. Upon launching the software, a wizard walks you through. Top 10 papers on surface wave analysis for geotechnical site. This paper introduces a new open source software, maswaves multichannel analysis of surface waves for.
Analysis and behaviour of surface wave dispersion for soft. Multichannel analysis of surface wave method with the. Masw dispersion analysis this is the first step of data processing in most of surfacewave methods. Though my method is robust where the surface wave is highly dispersed, i find that parameterization becomes ambiguous when the surface wave is multimodal, and so it is possible for misinterpretation of different modes of the surface wave. Arraybased measurements of surface wave dispersion and.
Jul 11, 2017 the basis of most surface wave analysis methods is accurate determination of the frequencydependent phase velocity of fundamentalmode rayleigh waves park et al. The passive masw method utilizes surface waves generated from ambient cultural. Swan is a software package for seismics data processing which allows to invert the. Optimized source distance can be beneficial for the quality of dispersion. Software for masw analysis is discussed in its required specifications.
Dispersion interpretation from synthetic seismograms and. Picking option directly on the spectrum graph to extract the dispersion curve. By repeating the above procedure for any given frequency, the surface wave velocity corresponding to a given wavelength is evaluated, and the dispersion curve is determined. We propose a method to invert surface wave dispersion data directly for 3d variations of shear wave speed, that is, without the intermediate step of phase or group velocity maps, using frequencydependent ray tracing and a waveletbased sparsityconstrained tomographic inversion. As well, the v4 manual demonstrates the sharper dispersioncurve imaging. Surface wave analysis for near surface applications. Multistation analysis of surface wave dispersion chihping lin, tzongsheng chang department of civil engineering, national chiao tung university, 1001 tahsueh road, hsinchu, taiwan, roc accepted 17 november 2003 abstract methods based on multistation recordings are presented for constructing the experimental dispersion curve of rayleigh waves. More accurate nearsurface characterization provides the information between the upholes and a better static solution bottom. In addition, various types of special analysis modules such as backscattering analysis and commonoffset section generation may be included for more advanced handling of surface wave data. Multichannel analysis of surface waves masw is a technique frequently used in geotechnical engineering and engineering geophysics to infer layered models of seismic shear wave velocities in the top tens to hundreds of meters of the subsurface. An initial assessment and its potential use in geology. Surface wave analysis aims at estimating the seismic shear wave velocity v s profile by solving an inverse problem of model parameter identification based on an experimental dispersion curve. The dispersion spectrum can be calculated in fk, fv or fp domain, where the fundamental a. As a result, water with a free surface is generally considered to be a dispersive medium.
Parkseis is the most comprehensive and uptodate masw software currently available on the market. A more detailed description of each method can be found in the previously cited references. The consistent performance in dispersion analysis for geotechnical surface wave investigations chik z. Surface wave analysis for near surface applications 1st edition. Tool for analysis of multichannel analysis of surface. The usw technique is an offshoot of the spectral analysis of surface waves sasw method used in evaluating material properties elastic moduli in the very near surface zone. Software for efficient surface wave inversion using mpi and gpus author.
The masw survey study concluded that the most consistent and beneficial karst terrain dispersion images were those obtained from the predicted optimal acquisition. Upon launching the software, a wizard walks you through the data analysis. Geogiga surface wave seismic analysis software refraction and reflection seismic software surface is able to process active surface waves with sasw and masw. Synthetic seismograms and multichannel analysis of surface. For the previous analysis of rayleigh waves in a halfspace. Surface wave analysis for near surface applications 1st. Shot gather analysis of the ground roll provides a surface wave dispersion curve top used during the inversion to build near surface velocity models.
Geogiga surface wave seismic analysis software refraction and. Earthquake engineering research center department of civil engg. Steve sloan, jason mckenna us army corps of engineers. Surface wave twostation dispersion analysis gui software in matlab 2. Sign up automatic surface wave twostation dispersion analysis matlab gui. Tool for analysis of masw field data and evaluation of. Surfacewave inversion is the method by which elastic properties, density, and thickness of layers in the subsurface are obtained through analysis of surfacewave dispersion. The robust forward modeling and the global genetic algorithm ga assure the quick convergence of inversion. Multi channel analysis of surface wave masw testing for. Explore novotechs software and get 35% off your next purchase.
Guidelines for the good practice of surface wave analysis. New insights into the lithosphere beneath the superior. This can result in the activepassive combined analysis of surface waves for the. The dispersion properties of surface waves can be useful for estimating swave velocity of the near surface. Multichannel analysis of surface waves exploration services. Dispersion modeling project us department of energy. The goal is to estimate one or more dispersion curves that are in turn passed into the next step of inversion process, which tries to find a proper layer shearvelocity, vs model whose theoretical dispersion curves. Joseph kump was the primary software and algorithm developer and contributed to writing this manuscript.
Surface wave analysis and its application to the calculation. Direct inversion of surface wave dispersion for three. Tool for analysis of multichannel analysis of surface waves masw. Basically, after field geometry is encoded, the next step is to process for dispersion information. Seisimagersw surface wave analysis software passive microtremor and active source surface wave data analysis calculates phase velocity and automatically picks dispersion curve time msperforms inversion to iteratively seek 1d swave velocity v s curve or 2d v s crosssection allows active and passive source dispersion curves. The higher frequency data from a sledgehammer source that travels through shallower depths can be combined with lower frequency data from microtremors that travel through greater depths. Joseph kump was the primary software and algorithm developer and. Multichannel analysis of surface waves accelerated maswaccelerated. It is a very easytouse application that, with simple steps, performs the analysis of the shear waves velocities vs.
The goal is to estimate one or more dispersion curves that are in turn passed into the next step of inversion process, which tries to find a proper layer shear. Combine the results for one highresolution plot of swave velocity. This paper introduces a new opensource software, maswaves, for processing and analysing multichannel surface wave records using the masw method. Water waves, in this context, are waves propagating on the water surface, with gravity and surface tension as the restoring forces. Surface wave inversion is the method by which elastic properties, density, and thickness of layers in the subsurface are obtained through analysis of surface wave dispersion. During the spectral processing phase the user can view the dispersion of a customizable synthetic model and the results. Though my method is robust where the surface wave is highly dispersed, i find that parameterization becomes ambiguous when the surface wave is multimodal, and so it is possible for misinterpretation of. The dispersion spectrum can be calculated in fk, fv, or fp domain, where the fundamental and highermode dispersion curves are interactively picked. Easy data import seg2, segd, segy, segb and more formats supported, intuitive geometry assignement, fast and.
Kgssurfseis masw softwareintroduction to masw acquisition. We analyse dispersion and attenuation of surface waves at free surfaces of possible vacuumporoelastic media. Tool for analysis of multichannel analysis of surface waves. However, most available software for surface wave analysis show. The fundamental mode of the surface wave is the signal used for the analysis. It is a very easytouse application that, with simple steps, performs the analysis of the shear waves velocities vs the software allows the inversion using more modes. Stewart abstract in a real layered earth, surface waves are dispersive with multiple modes. Advanced processing software is used to process the data. The basis of most surface wave analysis methods is accurate determination of the frequencydependent phase velocity of fundamentalmode rayleigh waves park et al. Depending on the nature of the seismic source the multichannel analysis of surface waves masw method can be categorized as active or passive.
After the main group of rayleigh an surface waves dispersion curves of eurasian earthquakes. We aim to accelerate masw calculations by capitalizing on modern computer hardware available in the workstations of most engineers. Masw multichannel analysis of surface wave in the radexpro seismic software. Surface is able to process active surface waves with sasw and masw.
Mar 04, 2020 multichannel analysis of surface waves masw is a technique frequently used in geotechnical engineering and engineering geophysics to infer layered models of seismic shear wave velocities in the top tens to hundreds of meters of the subsurface. Multichannel analysis of surface waves easy masw geostru. The dispersion properties of surface waves can be useful for estimating s wave velocity of the near surface. Dispersion analysis involved generation of dispersionimage called overtone and extraction of. Surface wave analysis for near surface applications presents the foundational tools and techniques necessary to properly analyze surface wave propagation nowadays performed for a number of. Dispersion, surface wave, finite element, frequencywave number analysis, soft layer. Pdf surface wave analysis for near surface applications. Geometric dispersion of surface waves in vertically heterogeneous media.
Surfacewave analysis for estimating nearsurface properties. The entire inversion process requires the gathering of seismic data, the creation of dispersion curves, and finally the inference of subsurface properties. Sasw utilizes the phenomenon of the surface wave dispersion, i. Dispersion interpretation from synthetic seismograms and multichannel analysis of surface waves masw j. Surface waves are easy to record and loaded with information about the subsurface. Simultaneous measurement and inversion of surface wave dispersion and attenuation curves. Surface wave analysis for estimating near surface properties khaled al dulaijan and robert r. Because the swave velocity is the dominant property of the fundamental mode of rayleigh wave dispersion data, swave velocities can be quickly estimated from surfacewave data. From analysis of phase information for each frequency, the velocity of the waves is determined between two.
Dispersion algorithm for dispersion analysis, the phaseshift method by park et al. Masw or sasw multichannel analysis of surface waves spectral. Acquisition of active multichannel analysis of surface waves. Geogiga surface wave seismic analysis software refraction. Confidence in the dispersion curve can be estimated through a measure of signaltonoise ratio sn displayed along with the curve. Tyler schwenk, richard miller, julian ivanov, kansas geological survey, the university of kansas. The consistent performance in dispersion analysis for. Seismic wave analysis for near surface applications presents the foundational tools necessary to properly analyze surface waves acquired according to both active and. Acquisition of active multichannel analysis of surface. The next versions of the softwaresurfseis 2, 3, and 4have included new.
This can result in the combined activepassive analysis of surface waves for the. Surface wave analysis for near surface applications presents the foundational tools and techniques necessary to properly analyze surfacewave propagation nowadays performed for. The entire inversion process requires the gathering of seismic data, the creation of. Applications range from seismic hazard studies, geotechnical surveys and the exploration of extraterrestrial bodies. Shot gather analysis of the ground roll provides a surface wave dispersion curve top used during the inversion to build nearsurface velocity models. The sval program petr kolinsky institute of rock structure and mechanics, academy of sciences of the czech republic, prague. Seismic wave analysis for near surface applications presents the foundational tools necessary to properly analyze surface waves acquired according to both active and passive techniques. The software maswaves is designed to perform the dispersion analysis and the inversion analysis. Acquisition of active multichannel analysis of surface waves masw data in karst terrain by ghassan salem alsulaimani. The surface wave analysis is typically implemented with three sequential steps. The only type of surface wave which propagates along the surface of a uniform medium is a rayleigh wave. Multichannel analysis of surface waves accelerated. To cope with noise and dispersion in the data, i introduce two cost functions. Our group has developed a number of codes and softwares for seismic data analysis, seismic tomography, joint inversion, etc, which are listed as the following.
Tool for analysis of masw field data and evaluation of shear. Ambient noise crosscorrelation codes for daily long sac format data in matlab 3. Performs inversion to iteratively seek 1d swave velocity. The use of this method means that the phase effects of the earthquake source function and the common path to the station pair are cancelled out, allowing a. There are basically two inversion processes, a simple and. We aim to accelerate masw calculations by capitalizing on modern computer hardware available in the workstations of most.
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