Jun 21, 2014 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. Particle motion consists of alternating transverse motions. Seismic wave propagation in stratified media brian kennett. The emphasis is on the propagation of seismic waves in. Nov 18, 2019 finitedifference seismic wave simulation. Seismic lowfrequency effects figure 4 lowfrequency reflective image mapping of a wateroil contact boundary and well content. Animations are provided to view wave propagation in a 3dimensional solid for compressional p, shear s, rayleigh r and love l waves. Further information on seismic waves, wave propagation in the earth, and visualizations of. Pdf seismic wave propagation and scattering in the. Modeling can help understand the complex seismic waves. Animations of these images can be found in the folder noted on the first page of this activity. Physics of acoustic wave propagation the theory of acoustic wave propagation is now described. Fundamentals of seismic wave propagation fundamentals of seismic wave propagation presents a comprehensive introduction to the propagation of highfrequency, bodywaves in elastodynamics. This is a collection of matlab and python scripts to simulate seismic wave propagation in 1d and 2d.
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. Geophysics 20012005 china university of geosciences beijing research interests physics of seismic wave propagation in earth media, seismic tomographymigration methods, co2 monitoring, microseismic imaging, groundpenetrating radar, seismic modeling of glacial ice honors and awards. Measurements of seismic wave attenuation using multiple scs waves. Modelling seismic wave propagation for geophysical imaging 10 willbesetbyintech from a maximum value.
This work shows the strong effect of including the variation of wave speed through the top thirty meters of the earth. Pdf glossary definition of the subject introduction the evolution of numerical methods and grids 3d. Pdf seismic wave propagation in media with complex. To aid in seeing that the particle motion is purely horizontal, focus on the y axis red line as the wave propagates through it. The theory of seismic wave propagation in acoustic, elastic and anisotropic media is developed to allow seismic waves to be modelled in complex, realistic threedimensional earth models. These waves alternately compress and pull out the solid rock. This viscoacoustic wave equation can model approximate constantq attenuation and dispersion behaviour of seismic waves in the relevant seismic frequency band. Introduction when considering wave propagation and reflectivity in weakly attenuative media or corrections for attenuation effects in seismic data processing, the quality factor q is a convenient property. Seismic ground motion response using shake, eera and nera for srs soil profile jay amin structural mechanics, principal engineer shawn carey, phd, pe structural mechanics, structural lead. In any current course on wave propagation, it seemed essential to mention, at least, the quite amazing results being found on exact, solu tions for the kortewegde vries equation and related equations. It separates the problem of wave propagation in a cylindrically or spheri. Types of seismic waves there are several different kinds of seismic waves, and they all move in different ways. Numerical simulation of seismic wave propagation in. Computational modeling of wave propagation in a geophysical.
Easytouse controls speedup, slowdown, or reverse the wave propagation. Seismic wave demonstrations and animations 1 purdue university. Pdf modelling seismic wave propagation for geophysical imaging. Detection and identification of seismic pwaves using. Seismic waves is a browserbased tool to visualize the propagation of seismic waves from historic earthquakes through earths interior and around its surface. Every point on the wave front is a source of a new wave that travels out of it in the form of spherical shells. Fundamentals of seismic wave propagation by chris chapman. Virieux 1986, which is solved by finitedifferences on a staggeredgrid. Daniel peter, dimitri komatitsch, yang luo, roland martin, nicolas le goff, emanuele casarotti, pieyre le loher, federica magnoni, qinya liu, celine blitz, tarje nissenmeyer, piero basini, jeroen tromp, forward and adjoint simulations of seismic wave propagation on fully unstructured hexahedral meshes, geophysical journal international, volume 186, issue 2, august 2011, pages 721739.
The key idea is to map each of the six sides of a cube to the surface of the sphere. A principal difference among p, sv, and sh wavefields is the manner in which they cause rock particles to oscillate. Seismic wave propagation in stratified media anu press. Seismic waves are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. In the past few decades, this has been extensively studied, e. By carefully examining these seismic wave fronts and their propagation, the seismic waves tool illustrates how earthquakes can provide evidence that allows us.
Pwaves are longitudinal waves, that is, they travel along the direction of wave propagation. Arbitrary high order finite volume schemes for seismic wave propagation 3 2 anelastic wave equations the anelastic wave propagation can be described by modifying the constitutive relation, i. Timereverse modelling of acoustic wave propagation in. Seismic rays are used instead of the wave front to describe the wave propagation. Seismic waves generated both by natural earthquakes and by manmade. Seismic wave motionbraile compressional p wave propagation in a slinky. The hybrid method is a combination of analytic and numerical methods, with the numerical method finite difference, or fd applied in the heterogeneous anisotropic region only and the analytic method generalized ray theory, or grt. Pdf seismic waves generated both by natural earthquakes and by manmade sources have produced an enormous amount of information about the earths.
Forward and adjoint simulations of seismic wave propagation. The wave propagation is based on the firstorder acoustic wave equation in stressvelocity formulation e. Seismic anisotropy is the fundamental phenomenon of wave propagation in the earths interior. Seismic ground motion response using shake, eera and nera for. Seismic wave propagation in icy ocean worlds arxiv. Numerical modeling of wave behavior is critical for exploration and global seismology studies. The object of modern seismic analysis is to extract. In openswpc, a set of netcdf files and a list of these files associated with the. Considering only velocity anisotropy, wave propagation is wellmodeled by the anisotropic elasticwave equation. The propagation of shear s and compression p waves within the earth allows geologists to track seismic events and to identify subterranean structure. The numerical simulation of seismic wave propagation is a.
Arbitrary high order finite volume schemes for seismic. The detection of normalmode frequencies will likely provide the best constraints on mars interior, as noted by bolt. This parameter depends on the peak ground velocity pgv and the peak ground. Rock mass modeling approach for simulating wave propagation. Raypaths are lines that show the direction that the seismic wave is propagating. Seismic lowfrequency effects from oilsaturated reservoir zones. Nov 11, 2018 specfem2d simulates forward and adjoint seismic wave propagation in twodimensional acoustic, anelastic, poroelastic or coupled acousticanelasticporoelastic media, with convolution pml absorbing conditions. The propagation velocity of seismic waves depends on density and elasticity of the medium as well as the type of wave. Pdf a new seismic intensity parameter to estimate damage in. Wave propagation project wpp computational infrastructure for. Seismic waves are studied by geophysicists called seismologists. Modeling of seismic wave propagation at the scale of the.
Miller department of earth and environmental sciences university of michigan summary the seismic quality factor q is a measure of seismic wave attenuation due to the earths anelasticity. Full elastic anisotropy wave equation is often used to model the complexity of velocity anisotropy but it ignores attenuation anisotropy. An increase in element size, to adapt it to the variations of wave speed with depth, can be obtained by. Seismic wave propagation and scattering in the heterogeneous.
Considering only velocity anisotropy, wave propagation is wellmodeled by the anisotropic elastic wave equation. Comparing the vibration curves for the two medium points chosen in advance, the propagation of the given seismic wave can be determined. Estimation of nearsurface shearwave velocity by inversion of rayleigh waves jianghai xia. Seismic wave propagation and imaging in heterogenous media. Abstract the shearwaveswavevelocityofnearsurfacematerials soil, rocks, pavement and its effect on seismicwave propagation are of fundamental interest in many. Simulations of seismic wave propagation on mars modes, surface wave and longperiod body waves in several past studies see lognonne and mosser 1993 up to 10 sec and lognonne et al. This page intentionally left blank iu jeofizik kulubu. These waves travel through massive rock and liquid. The occurrence of an earthquake gives rise to seismic waves. This book provides a consistent and thorough development of modelling methods widely used in elastic wave propagation ranging from the whole earth, through re. Bob butler taps the back of his hand to generate a compressional p wave through the suspended slinky. Arbitrary high order finite volume schemes for seismic wave.
Approximating constantq seismic propagation in the time domain tieyuan zhu 1. The spectralelement method is implemented in the regional scale for a 3d integrated southern california velocity model. However, rock mass modeling approach for simulating wave. Animations are provided to view wave propagation in a 3dimensional solid for compressional p. Modelling seismic wave propagation for geophysical imaging. Seismic wave propagation and imaging in heterogenous media yijian meng university of toronto, on, canada yijian. At such an interface, the energy within an incident seismic wave is partitioned into. Cambridge core solid earth geophysics fundamentals of seismic wave propagation by chris chapman.
A timesequential movie of the seismic wave propagation associated with fig. 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. Harris 1 1 stanford university, stanford, california, 94305, usa and 2 istituto nazionale di oceanografia e di geofisica sperimentale ogs. Approximating constantq seismic propagation in the time domain. Seismic wave fields are recorded by a seismometer, hydrophone in water, or accelerometer. Kennett title page contents jj ii j i page 8 of 497 back full screen close quit rs s e anu preface the primary sources of data in seismology are seismic records at the earths surface of natural or manmade events. Measurements of seismic wave attenuation using multiple scs waves honors thesis joshua c. Seismic wave propagation in media with complex geometries, simulation of s7891. The detection of normalmode frequencies will likely.
Lecture notes nearsurface geophysical imaging earth. Spectralelement simulations of 3d seismic wave propagation. Morozov university of saskatchewan summary the propagation, reflectivity, and attenuation of seismic waves in bitumenrich rocks and heavy oils can be difficult to explain by the traditional viscoelastic concepts, such as the q factor. Seismic wave animations are used to illustrate different types of wave propagation through elastic materials. Q viscoacoustic wave equation for modelling wave propagation in attenuating media. They are the energy that travels through the earth and is recorded on seismographs. A new seismic intensity parameter to estimate damage in buried pipelines due to seismic wave propagation is proposed.
I have tried to illustrate many of the seismic wave phenomena with actual seismograms and i extend my thanks to the many people who have helped me in my search for such examples. Modeling wave propagation in anisotropic media is the key element of seismic imaging and fullwaveform inversion of anisotropic parameters. Reflection and transmission of seismic waves in layered media at an interface between two rock layers there is generally a change in propagation velocity resulting from difference in physical properties of the two layers. Seismic waves viewer incorporated research institutions for. Particle motion is horizontal and perpendicular to the direction of propagation transverse. This thesis presents a concise introduction to the spectralelement method and its applications to the simulation of seismic wave propagation in 3d earth models. 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. Illingworth, who have done much to shape my ideas on seismic wave propagation, for their help and criticism.
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