文件列表:

FD3S_1.1 (0, 2017-02-23)
FD3S_1.1\DATA (0, 2006-08-03)
FD3S_1.1\DATA\COORDINATES (0, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\xco_0 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\xco_1 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\xco_2 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\xco_3 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\xco_4 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\xco_5 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\xco_6 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\xco_7 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\yco_0 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\yco_1 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\yco_2 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\yco_3 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\yco_4 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\yco_5 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\yco_6 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\yco_7 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\zco_0 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\zco_1 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\zco_2 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\zco_3 (1616, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\zco_4 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\zco_5 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\zco_6 (1600, 2017-02-23)
FD3S_1.1\DATA\COORDINATES\zco_7 (1600, 2017-02-23)
FD3S_1.1\DATA\LOGFILES (0, 2017-02-23)
FD3S_1.1\DATA\LOGFILES\logfile0 (913, 2017-02-23)
FD3S_1.1\DATA\LOGFILES\logfile1 (787, 2017-02-23)
FD3S_1.1\DATA\LOGFILES\logfile2 (787, 2017-02-23)
FD3S_1.1\DATA\LOGFILES\logfile3 (787, 2017-02-23)
FD3S_1.1\DATA\LOGFILES\logfile4 (930, 2017-02-23)
FD3S_1.1\DATA\LOGFILES\logfile5 (787, 2017-02-23)
FD3S_1.1\DATA\LOGFILES\logfile6 (787, 2017-02-23)
FD3S_1.1\DATA\LOGFILES\logfile7 (787, 2017-02-23)
FD3S_1.1\DATA\OUTPUT (0, 2006-08-03)
FD3S_1.1\MATLAB (0, 2006-08-03)
FD3S_1.1\MATLAB\Par (2003, 2006-07-31)
FD3S_1.1\MATLAB\fgauss.m (55, 2006-07-06)
... ...

This directory contains the source code for high-order finite difference 3D elastic wave propagation on staggered grids for spherical geometry. The serial algorithm has been written to run on the Pacific Sierra F90 to F77 translator. ****** COMPILATION *********************************************************** To compile the code, type make to run the makefile. ******* STRUCTURE AND COMPONENTS OF THE ALGORITHM **************************** The makefile connects the different subfiles of the code. The declaration of global parameters and variables is accomplished by common_global.h The main program is called fd3s_main.f90 including all other subroutines by call statements. At first, parameters are read in from the file "Par" in the routine fd3s_input.f90. fd3s_init.f90 initializes all further values such as model space, source and receiver parameters, absorbing boundaries, and FD operator specifications. The subroutine fd3s_model.f90 computes the background model as chosen from: - Homogeneous half space - Two-layered model (discontinuity at 240km depth) - isotropic part of PREM (Dziewonski and Anderson, 1***1) - Slab model read in from files for each node as perturbation values for PREM fd3s_check.f90 writes all important setup features interactively and to log-files, including a file designed to be loaded by Matlab. fd3s_evolution.f90 solves the velocity-stress formalism of the elastodynamic equations in spherical geometry by finite difference derivatives of variable operator length and second-order time extrapolation. Two different surface treatments are involved as well as switches for elastic interpolation, and computation of curl and divergence for the velocity field. Interpolation and partial derivatives are explicitely calculated in subroutine fd3s_oper.f90. fd3s_output saves seismograms of the velocity components and/or curl and divergence to file. Additionally, snapshots of the velocity field, stress tensor trace, curl and divergenve of velocities can be written out on the surface and two vertical planes, usually through the hypocenter. It is recommended to insert delta functions for seismogram simulations to be able to alter the frequencies afterwards. In this case, snapshots are automatically excluded. ********** Parameter control ************************************************* Parameter settings are undertaken within the file Par, together with params.h for amount of grid points. The amount of grid points should be derived together with the range of model space and number of nodes used by applying Equation (2.26) of the Diplom Thesis. After defining a background model, the time increment can be calculated from the numerical stability criterion for spherical geometry (Equ. (2.25)) which is also written out while running the program. The highest value for the stability factor (usually from the phi-axis of the lowermost node) should then act as a constraint on the time increment. From that value, the total amount of time steps can be chosen according to desired total length of wave propagation. Values for the approximate frequency resolution when using a delta pulse are written out as well. It is therefore recommended to run several simulations of one time step to account for the best fit between time increment and frequency resolution. Changing parameters of params.h requires a new compilation, while changing the Par file can be done upon the same executable. Especially due to the times spent on compiling on the Hitachi, the values of params.h should be chosen at first. ********** Running the Program *********************************************** The compilation produces the executable main.x To run this file type main.x < Par ********* File storage and additional folders ******************************** Object files of the compilation process are stored in a directory called OBJECTS as seen in the makefile. In the case of the specific Par file shown here, the directory containing the output data is called DATA as seen in the definition of the parameter 'seisfile'. The log files are written into the folder 'output' as seen from the parameter 'outfile' in fd3s_main.f90. All those folders must obviously be created if these settings are used. The output files of seismograms are filename0_x, filename0_y,filename0_z. ****************************************************************************** This algorithm has been developed during the Diploma Thesis of Tarje Nissen-Meyer on the basis of a code written by Prof. Heiner Igel, both at the Institute of Geophysics of the Ludwig-Maximilians-University Munich, Germany until August 2001. Copyright by Tarje Nissen-Meyer, 2002 Further information: tarje@geophysik.uni-muenchen.de Last change: March 9th 2002

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