Numerical simulation of seismic wave propagation in. The knowledge of exact numerical value of the seismic wave propagation velocity is a necessary parameter for the determination of unknown location of the seismic wave source 48. A shear or transverse body seismic wave, with motion perpendicular to the direction of wave propagation. Pdf fundamentals of seismic wave propagation by chris chapman. In the verification context, wave propagation in earth is divided into teleseismic distances greater than 2000 kilometers paths and regional distances less than 2000 kilometers paths. Citeseerx citation query propagation of elastic waves in. For a deeper understanding of seismic wave propagation in a tunnel environment, numerical simulations using the spectral element method sem and the nodal discontinuous galerkin method ndg are. Pwave swave rwave lwave to view files, click on the file names to view in browser, or right click on the file name, select open with, and select windows picture and fax viewer. Wave characteristics and particle motions of these wave types can be easily illustrated using the seismic wave animations. Modelling seismic wave propagation for geophysical imaging 10 willbesetbyintech from a maximum value. Types of seismic waves there are several different kinds of seismic waves, and they all move in different ways. If you want to create your own images, you can do this by fetching the 5minute world topographic file etopo5.
This tutorial is available for viewing with a browser html file and for. Seismiceruption has shaded terrain images which are savedscreen images. Seismic waves are studied by geophysicists called seismologists. I sh waves by rushan wu, shengwen jin, and xiaobi xie abstract the great advantages of oneway propagation methods, such as the generalized screen propagators gsp method, are the fast speed of computation, often. Seismic waves practice questions base your answer to question 1 on the diagram below, which shows models of two types of earthquake waves. These waves propagate through a 3d geologic model, and are simulated as synthetic seismograms or other graphical output. The general theory of propagation of seismic wave fields of signal type is presented in a mathematically precise and physically descriptive form. Seismic wave propagation simulations on lowpower and performancecentric manycores marcio castroa, emilio francesquinib, fabrice dupros c, hideo aochi, philippe o. A local adaptive method for the numerical approximation in. Propagation of seismic wave fields in layered media. In the case of seismic waves, energy is propagated through small displacements of the earth away from equilibrium. Seismic wave propagation in fully anisotropic axisymmetric.
Energy propagates away from seismic source with a distinct pattern. Body waves s waves secondary waves it is slower than a p wave and can only move through solid rock, not through any liquid medium. The length of simulation is propagated for 1 s using a time step of 0. The elastic parameters govern the velocity with which seismic waves propagate. These are distinguished from seismic intensity scales that categorize the intensity or severity of ground shaking quaking caused by an earthquake at a given location. Seismic magnitude scales are used to describe the overall strength or size of an earthquake.
Stable and efficient modeling of anelastic attenuation in seismic wave propagation volume 12 issue 1 n. This code is equipped with a frequencyindependent attenuation model based on the generalized zener body and an. Seismic wave propagation and scattering in heterogeneous. Seismic wave propagation and seismic tomography springerlink skip to main content. The programs seismiceruption and seismic waves can be used by anyone free of charge. Longperiod p waves are very weak on hglp seismograms of explosions, but longperiod sv waves are seen. Comparing the vibration curves for the two medium points chosen in advance, the propagation of the given seismic wave can be determined. This is an important theory in its own right because explorationists often assume that wave propagation in rocks can be approximated by acoustic theory so that they can simplify their data processing algorithms. Long period body wave spectra can be used to fix the depth of crustal earthquakes. Among various numerical methods, the finitedifference method is the dominant method in the modeling of earthquake motion. A wave is a representation of the propagation of energy. This chapter develops the basic principles of seismic tomography and serves as a general introduction to this book.
The concept of linear slip interfaces is used as a boundary condition to the. This thesis describes the development of numerical fluxes to simulate seismic wave propagation across fractures. The second type, or waves s, consists of wave propagation of shear, where the particles move in a direction perpendicular to the direction of propagation of the disturbance figure b. Seismic waves are initiated by earthquake, explosive, andor other sources. A seismic wave that travels across the surface of the earth as opposed to through it.
Simulating seismic wave propagation in 3d elastic media using staggeredgrid finite differences. Seismic waves can be generated by a sudden release of energy such as an earthquake, volcanic eruption, or chemical explosion. This method is based on the separation of the wave propagation equations derived from the constitutive law defining the stressstrain relation. A seismic wave is a mechanical disturbance or energy packet that can propagate from point to point in the earth. Numerical modeling of seismic wave propagation geophysics reprints series, no geophysics reprint series kelly, kevin r. Surface waves usually have larger amplitudes and longer wavelengths than body waves, and they travel more slowly than body waves. Consequences of the theory are discussed by comparing the phenomena in anisotropic and isotropic seismic media. The propagation velocity of seismic waves depends on density and elasticity of the medium as well as the type of wave. Whitham tata institute of fundamental research bombay 1979. In particular, the properties of plane and spherical waves at interfaces are described. Numerical modeling of seismic wave propagation and earthquake motion is an irreplaceable tool in investigation of the earths structure, processes in the earth, and particularly earthquake phenomena. Modelling seismic wave propagation for geophysical imaging.
Seismic waves can be generated by a sudden release of energy such as an earthquake. Seismic waves these are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. Seismic waves are generally referred to as elastics waves because they cause. Seismic wave propagation and imaging in heterogenous media. Stable and efficient modeling of anelastic attenuation in. Higher order thinking skills goals for this activity compare and contrast the difference between p and s seismic waves based on the direction of particle motion relative to. These waves propagate through a 3d geologic model, and are simulated as synthetic seismograms or. Seismic anisotropy describes directional dependence of seismic wave speeds and occurs in the earth for various reasons. To download the files to your computer, right click on the file name and select save target as. Additional suggestions for experiments with water waves are contained in zubrowski 1994. Seismic wave propagation in stratified media on jstor. E3d is capable of simulating seismic wave propagation in a 3d heterogeneous earth. Seismic wave propagation in stratified media book description. Pdf numerical modelling of seismic wave propagation in.
The main objectives were to determine the frequency and energy of seismic signatures, and investigate attenuation, patterns of azimuthal radiation from source regions, and methods of determining the type of motion at the source. Workshop on geophysical data analysis and assimilation andreas fichtner 29 october 3 november, 2012. Codes for wave propagation and earthquake dynamics. They are the energy that travels through the earth and is recorded on seismographs. The equation of motion for a continuum can be written as. Magnitudes are usually determined from measurements of an earthquakes seismic waves as recorded on a. In previous studies, the auxiliary differential equation ade method has been applied to 2d seismicwave propagation modelling in viscoelastic media.
Basic relations and notions of the theory are given for general cases of the anisotropy of a medium. In the verification context, wave propagation in earth is divided into teleseismic distances greater than 2000. Many different types of rays and seismic signals are illustrated, in order to set the scene for the rest of this book. Kennett title page contents jj ii j i page 3 of 497 back full screen close quit rs s e anu 2 coupled equations for seismic waves 46 2. Modelling seismic wave propagation for geophysical imaging 3 in the entire domain or at the scale of an elementary element of a given mesh describing the medium structure.
The amplification of seismic waves in surface soil layers is mainly due to the velocity contrast between these layers and, possibly, to topographic effects around. The emphasis is on the propagation of seismic waves in realistic earth models, and the way in which this can be understood in terms of the re. They are the energy that travels through the earth and recorded on seismographs. We will show that two types of solutions are possible. Seismic waves are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. The theoretical development is physically based and is closely tied to the nature of the seismograms observed across a wide range of distance scales from a few kilometres as in shallow reflection work for geophysical prospecting, to many thousands of kilometres for major earthquakes.
Introduction to seismic wave propagation wed, sept 9, 2009 today we are going to discuss about the following issues. Seismic wave propagation in stratified media research school of. The study used two sets of receiver arrangements, and one shot location. Pdf seismic waves generated both by natural earthquakes and by manmade sources have produced an enormous amount of information. The most important information on the constitution of the earths interior has been obtained from studies of seismic body waves longitudinal and. Most seismic sources can be approximated spatially as point sources. Seismic wave fields are recorded by a seismometer, hydrophone in water, or accelerometer. The report summarizes one year of theoretical and applied research on propagation of seismic waves and techniques for analyzing data. Numerical modeling of seismic wave propagation geophysics. We have developed an opensource software package, opensource seismic wave propagation code openswpc, for parallel numerical simulations of seismic wave propagation in 3d and 2d psv and sh viscoelastic media based on the finite difference method in localtoregional scales. Modeling of seismic wave propagation at the scale of the. Model a best represents the motion of earthquake waves called 1 pwaves compressional waves that travel faster than swaves shear waves shown in model b. Seismic wave propagation in icy ocean worlds arxiv. Nowack and others published fundamentals of seismic wave propagation by chris chapman find, read and cite all the.
The material has been prepared to use the navigation facilities of adobe pdf. Seismic waves and the slinky teachers guide page 1 of 40. For electromagnetic waves, propagation may occur in a vacuum as well as in a material medium. A principal difference among p, sv, and sh wavefields is the manner in which they cause rock particles to oscillate. Seismic wave propagation and seismic tomography springerlink. Seismic wave propagation and scattering in heterogeneous crustal waveguides using screen propagators. Simulating seismic wave propagation in 3d elastic media using staggeredgrid finite differences robert w. Pdf modelling seismic wave propagation for geophysical.
For the numerical simulation of 2d earthquake dynamics, the spectral boundary integral equation code bimat is well suited for planar faults in homogeneous and bimaterial media, and the spectral element code sem2dpack is well suited for nonplanar faults in heterogeneous or nonlinear media. Wave propagation is any of the ways in which waves travel. Simulation of global seismic wave propagation through nonconforming curved finite element methods duration. See the section labeled seismic thermal load section. Bormann 2003, the iaspei standard seismic phase list, seismol. Pdf seismic wave propagation and scattering in the.
Pdf modelling seismic wave propagation for geophysical imaging. Modeling seismic wave propagation and amplification in 1d. A local adaptive method for the numerical approximation in seismic wave modelling. Tutorial soil overburden and seismic wave propagation in autopipe.
Numerical modeling of seismic wave propagation geophysics reprints series, no geophysics reprint series. Workshop on geophysical data analysis and assimilation. With respect to the direction of the oscillation relative to the propagation direction, we can distinguish between longitudinal wave and transverse waves. View of 3d grid used to illustrate seismic wave propagation. The first of them, called pwaves, consists of the transmission of compressions and rarefacciones of rock, similar to the propagation of the sound figure a. Receivers are placed in every grid point in the xy plane at the depth of 20 m. Animations are provided to view wave propagation in a 3dimensional solid for compressional p, shear s, rayleigh r and love l waves. Seismic wave propagation simulations on lowpower and. Whitham published for the tata institute of fundamental research, bombay springerverlag berlin heidelberg new york 1979.
This introductory chapter introduces the reader to the concepts of seismic waves plane waves, point sources, rays and travel times without math ematical detail or analysis. To examine the effects of the anisotropy in the medium on the wave, seismic wave propagation was modeled for different heterogeneous models with each having different scale length parameters. This book provides a consistent and thorough development of modelling methods widely used in elastic wave propagation ranging from the whole earth, through re. Model a best represents the motion of earthquake waves called 1 pwaves compressional waves that travel faster than swaves shear waves shown in model b 2 pwaves compressional waves that travel slower than s. Seismic wave propagation and earth models gfzpublic. Seismic wave propagation in nonlinear viscoelastic media.
Available formats pdf please select a format to send. Simulating seismic wave propagation in 3d elastic media using. This step in the procedure will calculate the dt value that is displayed on the soil properties dialog below. Simulating seismic wave propagation in 3d elastic media. Physics of acoustic wave propagation the theory of acoustic wave propagation is now described. In the continuum, a force applied across a surface, oriented by. Seismic wave propagation basic physical principles governing the propagation of seismic waves include generation, transmission, absorption and attenuation of the seismic wave in earth materials and the seismic waves reflection, refraction and diffraction characteristics at discontinuities. Body wave spectra, magnitudes, and focal mechanisms for events in from seismic zones of central asia have been determined.
Fundamental laws of dynamics require the conservation of linear and angular momentum in a galilean reference frame. Whitham published for the tata institute of fundamental research, bombay springerverlag berlin heidelberg new york. The large processing requirements of seismic wave propagation simulations make high performance computing hpc architectures a natural choice for their execution. Subjected to a p wave, particles move in the same direction that the wave is moving in, which is the direction that the energy is traveling in, and is sometimes called the direction of wave propagation.
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