3 edition of Benchmarking the two-dimensional finite difference synthetic seismogram code found in the catalog.
Benchmarking the two-dimensional finite difference synthetic seismogram code
Allen, J. M.
During the past six months, the two-dimensional finite difference synthetic seismogram code was installed and run on a number of different computer systems. The results were compared for timing, accuracy and the ease with which the code was adapted to each system. This report documents the software modifications and the method used to implement the finite difference code on each computer, and presents the results of the benchmark survey.
|Statement||by J. M. Allen and R. A. Stephen.|
|Series||WHOI -- 91-31., WHOI (Series) -- 91-31.|
|Contributions||Stephen, Ralph A., Woods Hole Oceanographic Institution.|
|The Physical Object|
|Pagination||20 p. :|
|Number of Pages||20|
Major advancements in the development of finite-difference and related synthetic seismogram modeling techniques over the past several years have significantly increased the ability to model heterogeneous structures of geophysical interest. 69 1 % This Matlab script solves the one-dimensional convection 2 % equation using a finite difference algorithm. The 3 % discretization uses central differences in space and forward 4 % Euler in time. 5 6 clear all; 7 close all; 8 9 % Number of points 10 Nx = 50; 11 x = linspace(0,1,Nx+1); 12 dx = 1/Nx; 13 14 % velocity 15 u = 1; 16 17 % Set final time 18 tfinal = ; 19 20 % Set timestep.
Finite Di erence Methods for Boundary Value Problems October 2, Finite Di erences October 2, 1 / Goals Learn steps to approximate BVPs using the Finite Di erence Method Start with two-point BVP (1D) Investigate common FD approximations for u0(x) and u00(x) in 1D Use FD quotients to write a system of di erence equations to solve. This book presents finite difference methods for solving partial differential equations (PDEs) and also general concepts like stability, boundary conditions etc. Material is in order of increasing complexity (from elliptic PDEs to hyperbolic systems) with related theory included in appendices.
Finite Difference Approximations In the previous chapter we discussed several conservation laws and demonstrated that these laws lead to partial differ-ential equations (PDEs). In this chapter, we will show how to approximate partial derivatives using ﬁnite differences. 46 Self-Assessment Before reading this chapter, you may wish to review. Although the earth is 3-dimensional (3-D), numerical simulations of wave propagation through laterally heterogeneous media are easier to formulate and more practical to use in 2-D. In this thesis, schemes to model seismic wave propagation through laterally varying structures with 2-D numerical algorithms are developed and applied to earthquake and explosion problems. In Chapter 1, 2-D.
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Two-dimensional (2-D) finite-difference (FD) synthetics, which fill the gap between fast 1-D analytic synthetics and time-consuming full 3-D synthetics in our ability to model seismograms, have been used in many studies.
We address several issues involving 2-D FD methods in generating global synthetic by: The proper simulation of the source requires special treatment for both tic seismograms computed for several models of exploration interest serve Cited by: Roughly speaking there are three types of methods to calculate synthetic seismograms.
The first type is numerical method, e.g., the finite difference method (Boore ), the finite element method (Bielak et al. ) and the spectral element method (Komatitsch and Tromp). Numerical methods are usually quite : Tianshi Liu, Haiming Zhang.
A general, two-dimensional, finite-difference algorithm is developed above for modeling variably saturated flow through porous media. The algorithm performs well over a broad range of problems, as demonstrated by its performance against published experimental data.
SYNTHETIC SEISMOGRAM GENERATION AND SEISMIC FACIES TO CORE LITHOLOGY CORRELATION FOR SITES, AND A.D. Cunningham2 and A.W. Droxler3 ABSTRACT One-dimensional synthetic seismograms are constructed from velocity and density measurements taken during Ocean Drill-ing Program (ODP) Leg at Sites, and We have pursued and compared two-dimensional (2-D) and three-dimensional (3-D) finite-difference (F-D) modeling of scattering from free surface topography.
A velocity–stress formulation of the full elastic wave equations are combined with exact boundary conditions for the surface topography and numerically discretized by an eighth-order F-D.
Synthetic seismograms have long been used in both the investigation of Earth structure and in the determination of earthquake source parameters. Until recently, however, there were relatively few methods for the routine generation of synthetic seismograms. Synthetic Seismogram Calculation using the Reflectivity Method.
Purpose of the code: Compute complete synthetic seismograms based on the following required elements: (1) A 1-D layered earth model containing Vp, Vs, density, Qa, Qb (Qs are quality factors of the material related to P and S speeds, inverse of attenuation) of each layer. Synthetic seismograms for any arbitrary source and receiver are then obtained simply by retrieving the eigenfunctions of all the modes in the database at the corresponding source and receiver depths.
It thus takes a few seconds to generate three-component waveforms up to Hz for a. Comparison of the three-component synthetic (red lines) and observed (black lines) waveforms at the 30 stations shown in Fig. All traces were band-pass filtered with corner periods of 30 s and s.
The IRIS network and station codes, and epicentral distance are. 11 Januarycan be divided into two major topics: Finite-Difference synthetic seismo-- grams for SH waves; and array analysis of the ground motions from the San Fernando Earthquake. In Section II, the accuracy and ease of application of the finite-difference method for.
past several years for generating synthetic seismograms and displaying the wavefields. This package consists of primarily a 2-dimensional 2nd-order explicit linear finite-difference (LFD) code.
LFD method has the advan-tage that the solution contains all conversions and all orders of multiple scattering. It permits examinations of. The finite difference equation at the grid point involves five grid points in a five-point stencil:, and.
The center is called the master grid point, where the finite difference equation is used to approximate the PDE. () 2D Poisson Equation (DirichletProblem). In principle, a system perturbation can be taken into account by mean estimated difference, between the Value computed in two independent calculation, one with a nominal system rather the second.
its a 1-D forward modeling coding on matlab. making synthetic seismogram for 6 layer model of having defined thicknesses and velocities and assumption is that density is. The book is aimed at geologists and geophysicists who may be new to interpreting seismic data, and although titled 3-D Seismic Interpretation there is much to be learned from within this volume about interpretation of other forms of seismic data.
For a comprehensive guide to getting the most out of seismic data [this book] has few competitors.’. COMPARISON OF SEISMIC REFLECTION DATA TO A SYNTHETIC SEISMOGRAM IN A VOLCANIC APRON AT SITE Thomas Funck2 and Holger Lykke-Andersen3 ABSTRACT The volcanic apron of Gran Canaria at Site is characterized by numerous, closely spaced reflectors, allowing a high-resolution stratigraphic correlation.
Moreover, the block-structured adaptive-mesh-refinement (SAMR) technique (Baker, ;Fakhari and Lee, ; Hittinger and Banks, ; Luitjens and Berzins, ;Ralf, ) is a branch to. THE FINITE-DIFFERENCE MODELLING OF EARTHQUAKE MOTIONS Waves and Ruptures Numerical simulation is an irreplaceable tool in earthquake ground motion research.
Among all the numerical methods in seismology, the ﬁnite-difference (FD) technique is the most widely used. Systems, methods, apparatus, and computer-readable media for multi-stage shape vector quantization USB2 (en) Qualcomm Incorporated: Systems, methods, apparatus, and computer-readable media for noise injection USB2 (en).
Utilize the dispersion relations and amplitude functions (eigenvalues) for Rayleigh or Love (SH) motion to determine the amplitude and phase spectrum for a layered half space at a given distance. Fourier transformation then yields the synthetic surface wave seismograms.
A large ./ Comparison of global synthetic seismograms calculated using the spherical D finite-difference method with observed long-period waveforms including data from the intra-Antarctic region.
In: Polar Science. ; Vol. 6, No. 2. pp. To find a numerical solution to equation (1) with finite difference methods, we first need to define a set of grid points in the domainDas follows: Choose a state step size Δx= b−a N (Nis an integer) and a time step size Δt, draw a set of horizontal and vertical lines across D, and get all intersection points (x j,t n), or simply (j,n), where x.