• Antelope Release 5.5 Linux 2.6.32-220.el6.x86_64 2015-04-21

 

NAME

dbrfcn - calculates receiver functions via frequency-domain deconvolution (css3.0)

SYNOPSIS

dbrfcn db dbout {orid | arid:azim} sta [pf-file-prefix]

SUPPORT


Contributed code: NO BRTT support.
THIS PIECE OF SOFTWARE WAS CONTRIBUTED BY THE ANTELOPE USER COMMUNITY. BRTT DISCLAIMS ALL OWNERSHIP, LIABILITY, AND SUPPORT FOR THIS PIECE OF SOFTWARE.

FOR HELP WITH THIS PIECE OF SOFTWARE, PLEASE CONTACT THE CONTRIBUTING AUTHOR.

DESCRIPTION

Dbfrcn is a database-communicative version of a frequency-domain deconvolution routine for calculating receiver functions. The input consists of a database dbin with Z, N, and E, along with a few inversion parameters. Prior to receiver function inversion, the routine selects a time window about desired P arrival, components are rotated into Z-R-T coordinates, records are optionally decimated, and detrended. Graphical display shows original 3 components, rotated horizontals, and 3 receiver functions for Z, R, and T components (Z component RF will be a delta-function if no filtering/stabilizing is applied). Two records are output, the standard R-component receiver function (channel "rfcn") and a T-component receiver function (channel "rf_T").

Deconvolution parameters are specified in a parameter file, and include a frequency-domain water level, a low-pass Gaussian filter, a high-pass Butterworth filter, and a phase shift to allow negative lag times to be seen.

Rotation and time-window selection are specified for a single station and either by event (orid) or by a combination of arrival pick and azimuth (arid:azim). Additional parameters are specified in an Antelope-style parameter file (ending in .pf), including all deconvolution parameters, the time window about P, a decimation interval, and a flag that chooses whether to plot or not. Sign conventions for rotated components are same as for "ahrot".

Decimation is specified by the "decimate" parameter, as an integer fraction of the current sample rate. Decimation is done by fourier-series truncation with a 6-pole two-way (zero phase) Butterworth filter applied at the new Nyquist frequency.

Amplitudes of receiver functions are rescaled to correct for filter effects. The scale factor is the peak amplitude of the "Z-component" receiver function, which would be unity if no scaling were applied. This factor is printed to screen, and its inverse is stored in calib field (as of 11/00).

COMMAND LINE ARGUMENTS

ENVIRONMENT

TAUP_PATH is used to specify travel-time calculation for P.

PARAMETER FILE

EXAMPLE

dbrfcn geytel rftestdb 62 ORGH dbrfcn

reads parameter file dbrfcn.pf, which looks like:

cat dbrfcn.pf

tstart		-10.
tend		50.
gaussfreq	0.5
hpfreq		0.02
phaseshift	10.0
waterlevel	0.01
decimate	0
graphics	1

LIBRARY

-ltr -lgpl2 -lol -lxcom -lgrx -ldb -lcoords -ltttaup -lresponse -lstock ./FFT/fftlib.a -lX11 -lF77 -lM77 -lsunmath -lm

SEE ALSO

dbtimerf, trrotd

BUGS AND CAVEATS

Unclear what happens if more than one Z, N, or E channel exists for a given station-time combination.

This method has all of the problems typically associated with frequency-domain deconvolutions.

AUTHOR

Geoff Abers, Boston University
Antelope User Group Contributed Software
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