Gpdc

Forward computation of dispersion curve

gpdc is a command line tool for computing phase or group velocity dispersion curve for either Rayleigh or Love waves given a layered 1D earth model in simple ascii format.

Command line help

Usage: gpdc [OPTIONS] [FILE] Compute dispersion curve for layered models given through stdin or FILE.

Format for layered models:

 Line 1  : <number of layers including half-space for first model>
 Line 2  : <thickness (m)> <Vp (m/s)> <Vs (m/s)> <Density (kg/m3)>[ <Qs> <Qp>]
 ....
 Line n  : 0 <Vp (m/s)> <Vs (m/s)> <Density (kg/m3)>[ <Qs> <Qp>]
 Line n+1: <number of layers including half-space for second model>
 ....

Quality factors are not mandatory. If not specified, pure elastic computation is performed. Any number of models can be given as input.

Gpdc options:

 -n <count>                Number of frequency samples (default=100)
 -L <n modes>              Number of Love modes (default=0)
 -R <n modes>              Number of Rayleigh modes (default=1)
 -grid <L | R>             Ouput a grid of the wave solutions (not set by default). The letter L or
                           R stands for Love or Rayleigh.
 -group                    Switches to group slowness (default=phase)
 -s <sampling>             Defines the sampling type:
                             period     regular sampling in period
                             frequency  regular sampling in frequency
                             log        regular sampling in log(frequency) (default)
 -min <min>                Minimum of range for dispersion curve (default=0.2)
 -max <max>                Maximum of range for dispersion curve (default=20)
 -vn <count>               Number of velocity samples (only for -grid, default=100)
 -vmin <min>               Minimum of range for velocity (only for -grid, default=100)
 -vmax <max>               Maximum of range for velocity (only for -grid, default=3000)

Generic options:

 -help <SECTION>           Show help about options. SECTION may be empty or: all, examples, generic,
                           gpdc
 -version                  Show version information
 -app-version              Show short version information
 -reportbug                Start bug report dialog, information about bug is passed through stdin.
                           This option is used internally to report bugs if option -nobugreport is
                           not specified.
 -reportint                Start bug report dialog, information about interruption is passed through
                           stdin. This option is used internally to report interruptions if option
                           -nobugreport is not specified.
 -nobugreport              Do not generate bug report in case of error

Examples:

        gpdc < test.model

 Calculate fundamental Rayleigh dispersion curve from 0.2 Hz to 20 Hz for model 'test.model'.

        gpdc -L 1 -R 2 < test.model

 Calculate fundamental Love mode and fundamental and first higher mode for Rayleigh.

        gpdc < test.model | figue -c

 Calculate the same dispersion curve and plot it.

        gpdc < test.model | figue -c -m dc.mkup

 Show the same dispersion curve on a log-log plot. 'dc.mkup' is a tar.gz file containing an xml
 description of the graphic format, it can be generated from figue's interface.

See also:

 gpell, gpprofile

Copyright:

 Copyright (c) 2002-2008 Marc Wathelet. All rights reserved.
 See http://www.geopsy.org for more information.

--Mao 15:12, 1 November 2008 (UTC)