Chapter 11 seismic tomography based on ray theory 7 11. The two main approaches to seismic tomography are traveltime tomography woodward, 1992. Since each ray path intersects with the model only at a small number of blocks. Hypocycloidal movement is preferred but linear tomography can produce good results. A site investigation through integration of reservoir properties, seismic imaging, and borehole and surface gravity data richard a. Seismic tomography and the assessment of uncertainty. We examine seismic tomography and computeraided tomography ct scans.
This site is like a library, use search box in the widget to get ebook that you want. To follow the class you should have a basic understanding in. Extracting seismic uncertainties from tomographic velocity. Reflection tomography, the determination of velocity distribution and reflector position from reflection traveltime data, is a very nonlinear invers we use cookies to enhance your experience.
Extracting seismic uncertainties from tomographic velocity inversion and their use in reservoir risk analysis abstract structural information in subsurface seismic images is critical for reservoir. The use of the fourier transform in our implementation enables a leastsquares inversion estimate of the radon domain, which is expedited. Decentralized seismic tomography computing in cyberphysical sensor systems liang zhao a, wenzhan song a,c, lei shi, xiaojing ye b, and junjie yang c adepartment of computer science, georgia. Seismic inversion aims to reconstruct a quantitative model of the earth subsurface, by solving an inverse problem based on seismic measurements. A breviary of seismic tomography download ebook pdf. My research interests are mainly focused on seismic interferometry and seismic tomography. Summary we present a full seismic waveform tomography for upper.
Pdf the inversion of seismic traveltime data for radially varying media was initially. Gu b a department of physics, university of toronto, toronto, ontario, canada m5s 1a7 b department of physics. Seismic tomography is an imaging technique that uses seismic. One of the simplest and most popular interpolants is pseudolinear interpolation, which in 3d cartesian.
Nonlinear crustal corrections in highresolution regional. Seismic tomography using local correlation functions. Click download or read online button to get a breviary of seismic tomography book now. Seismic tomography is a nonlinear and highdimensional optimization problem where a set of model parameters is sought to satisfy observations and additional a priori constraints. Seismic wave attenuation includes intrinsic attenuation and scattering attenuation. Linear array ambient noise adjoint tomography reveals. Distributed multigrid technique for seismic tomography in. Decentralized seismic tomography computing in cyber. Lateral tomography of the sella turcica is an important addition to the plain films.
Linear array ambient noise adjoint tomography reveals intense crustmantle interactions in north china craton chao zhang1,2, huajian yao 1, qinya liu2,3, ping zhang, yanhua o. If we represent some elastic property of the subsurface e. With the growth in computing power and in the amount of. We consider the conjugate gradient method for the normal equations in the solution of discrete illposed problems arising from seismic tomography. A bayesian linear model for seismic tomography 5 fig.
In crosshole seismic tomography, however, these datapicking errors may not be treated as random variables with a gaussian distribution and the solution may often be biased. The objective is to estimate the threedimensional structure of the earths interior from. Seismic interferometry is a relatively new seismology method that extracts useful information from a diffusive. We consider the conjugate gradient method for the normal equations in the solution of dis crete illposed problems arising from seismic tomography. Sambridge research school of earth sciences, australian national university, canberra act 0200. With the growth in computing power and in the amount of seismological data available, it soon became possible to carry out seismic tomography on a global scale. Seismic tomography is a technique for imaging the subsurface of the earth with seismic waves produced by earthquakes or explosions. Highresolution seismic tomography of long beach, ca using.
Case studies of seismic tomography and earthquake location in a. We use a linear approach of traveltime tomography that is. The objective is to estimate the threedimensional structure of the earths interior from data measured at its surface. We use a machine learningbased tomography method to obtain highresolution subsurface geophysical structure in long beach, ca, from seismic noise recorded on a largen array. Seismic attenuation tomography using the frequency shift method. P, s, and surface waves can be used for tomographic models of. Therefore, prior information of the survey field is needed to. The word tomography is derived from the greek word tomos meaning cut or slice and graphos meaning drawing. They differ from the traditional linearized inversion approach and offer five. Nonlinear reflection tomography geophysical journal. This project is dedicated to provide a python framework for seismic noise tomography, based on obspy and numerical python packages such as numpy and scipy.
Distribution of the seismic wave sources large earthquakes, blue and receivers seismic broadband stations, red that generated our. First arrival traveltime tomography using supervised. Seismic attenuation tomography using the frequency shift. Ambient noise tomography across the cascadia subduction zone using dense linear seismic arrays and double beamforming yadong wang, 1fanchi lin1 and kevin m. For example, with manual picking of phases, it is common. Seismic tomography has been a vital tool in probing the earths internal structure and enhancing our. However, 1, this is a highly nonlinear and illposed inverse problem. Adaptive mesh seismic tomography based on tetrahedral and. Passive seismic tomography and seismicity hazard analysis in deep underground mines xu ma abstract seismic tomography is a promising tool to help understand and evaluate the stability of a. Seismic tomography ii local earthquake tomography local earthquake tomography let is a common tool for imaging subsurface structure in seismically active areas. Comparisons of geophysical and medical imaging cseg. Fast, another publicly available tomography code, is based on.
Seismic tomography an overview sciencedirect topics. We now have a linear relationship between the travel time residual observations, ti, and the slowness perturbations, s. The method is used in radiology, archaeology, biology, atmospheric science, geophysics, oceanography. Ward,2 1department of geology and geophysics, the university of utah, salt lake city, ut 84112, usa.
We apply a linear bayesian model to seismic tomography, a highdimensional inverse problem in geophysics. The inversion of seismic traveltime data for radially varying media was initially investigated by herglotz, wiechert, and bateman the hwb method in the early part of the 20th century 1. Following that successful demonstration, the method of repeat tomography. Adaptation of back projection tomography to seismic travel. A desirable goal for divingwave tomography is to reformulate it as a linear problem in order to remove the initialmodel dependency. Adaptation of back projection tomography to seismic travel time problems eugene humphreys 1 and robert w. Pdf seismic attenuation tomography using the frequency. Seismic tomography i formulation seismic tomography combines data prediction with inversion in order to constrain 2d and 3d models of the earth represented by a signi.
Seismic tomography i research school of earth sciences. Clayton seismological laboratory, california institute of technology, pasadena a. Passive seismic tomography and seismicity hazard analysis. For the above linear tomographic problem, a number of. Decentralised seismic tomography computing in cyber. Geometric and level set tomography using ensemble kalman. Nonlinear crustal corrections in highresolution regional waveform seismic tomography federica marone. Tomography is imaging by sections or sectioning through the use of any kind of penetrating wave. Seismic tomography and monitoring of magmatic geothermal and natural. Conjugate gradient method for the solution of inverse.
1000 1300 1024 1493 1596 124 1264 808 1028 1510 1595 353 446 807 1515 1494 79 949 1454 89 1401 879 1208 444 816 1543 1050 987 660 207 1418 163 85 1048 357 368 1399