• Antelope Release 5.5 Mac OS X 10.8.5 2015-04-21

 

NAME

trrotd - rotates, detrends, and decimates a 3-component record set

SYNOPSIS

trrotd 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

Takes a 3-component set of traces from a css3.0 database and preprocesses them, making a new database that has the components rotated, windowed about a P arrival, detrended, and optionally decimated. This is useful preparation for a number of other procedures or handy in itself. Rotation is 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 the time window about P, a decimation interval, and a flag that chooses whether to plot or not.

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.

Sign conventions for rotated components are same as for "ahrot".

COMMAND LINE ARGUMENTS

ENVIRONMENT

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

PARAMETER FILE

EXAMPLE

trrotd geytel tempdb 62 ORGH trrotd

The parameter file trrotd.pf is used, and looks like:

cat trrotd.pf

tstart		-10.
tend		50.
decimate	4
graphics	0

This one decimates by factor of 4, and shows no graphics.

LIBRARY

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

SEE ALSO

pf

BUGS AND CAVEATS

Results are uncertain if "decimate" is not a power of 2.

Currently assumes channel name ending in Z is vertical, and N,E are some sort of horizontal (see rot.c). Uses hang to get horizontal rotations and vang for polarity, or assumes ZNE if these don't exist. Could be more general. All rec'ds multiplied by calib if it exists.

Results are uncertain if some number of channels other than 3 passes the station/orid or station/arid subsetting criteria.

Uses the fill option of trsplice, to add samples where small gaps exist (usually 1 sample). The samples are assumed to have the same value as the last good datum. This may introduce small artifacts, but it seems better than alternatives.

Output will fail if a record already exists with the same sta-chan-time in dbout. As well, problems occur if the directory wf/rfcns already has files for the sta-chan-time combination being attempted, even if the db pointing to those files may be different.

Currently only windows about predicted P time. Uses whatever default TT tables currently set (see $TAUP_PATH).

AUTHOR

Geoff Abers, Boston University
Antelope User Group Contributed Software
Printer icon