27.1.2 Program operation

The program first reads the parameter file, default codaq.par which must be in your current directory. It then reads the codaq.inp file with the events to analyze (also in current directory). The S-file names given here can, as shown in the examples above, be in the database or elsewhere, e.g. in your local directory. In the S-file, the name of the waveform file is given. If more than one waveform file is given, all files will be searched for the specified station and component. The program will first look in the current directory, and then in WAV and thereafter in the WAV database and other directories as given in the SEISAN.DEF file in DAT. The program can therefore work without moving the data from the database, however you can also move both the S- files and waveform files to your local directory. Remember that the S-files must be updated in order to have origin time, since the program uses the origin time and P arrival times from the S-files.

Running the program:

Type codaq, the program asks about output:

0: Only q is calculated, ente ris 0 for default
1: Q is calculated and a plot on the tek screen is shown
2: Q                                                    ,
   and at the same time hard copy plots are made.
3: Q is calculated and hard copy plots are made, but
   no screen plot.

Parameter file, name codaq.par is default (return)
   Just hit return if default file, otherwise give name.

File with event stations, codaq.inp is default (return)
   Just hit return if default file, otherwise give name.

The program will now start to run. Alterantively, the progran can be started with arguments on the promt line:

codaq n parameter-file data-file

or alternatively when doing channel averages

codaq -c n parameter-file data-file

and no questions are asked. n is the choice 0 to 3 above.

If no plot is chosen, one line will appear on the screen for each station used and one for each frequency. The program will start a new page for each new event. If you are plotting on the screen, you will therefore have to hit return to get the next plot. The screen might not have been filled out if there are few data.

All questions will appear in the text window. At the end, a summary is given, which is the same as logged in the output file codaq.out.

The abbreviations are:

H: Focal depth
M: Magnitude
TP: P travel time
TC: Start time of coda window relative to origin time
F: Frequency
Q: Corresponding coda q, if 0 value is \bgroup\color{black}$ >$\egroup 10000 or negative
S/N: Signal to noise ratio AV
Q: Average q
SD: Standard deviation for average
NT: Total number of q values at all frequencies
N: Number of q values at given frequency
q: Average of q values
1/q: q is calculated as 1/q averages, probably the best to use
f:1/q: Q values calculated using the relation derived from the 1/q averages
q = q0*f**v obtained with the average 1/q-values
cq0: Constant q0 obtained using the fixed user selected v
v: Constant v determined
cor: Correlation coefficient on determining q vs f
corr: Average correlation coefficients of individual codaq calculations when fitting the envelope, both average and standard deviation is given

If a station is not present or no P is read, a message will be given. The program will search for the first P arrival time in the S-file. If several are present for the same station, it will use the first.

Peter Voss : Tue Jun 8 13:38:42 UTC 2021