This section contains the main program CODAQ to calculate coda Q, program CODAQ_AREA to sort output from CODAQ into areal bins and a help program AVQ to average Q-relations.
The program will calculate coda Q (hereafter called Q) for a series of events and stations at given frequencies. On completion, the average values are calculated and a Q vs f curve is fitted to the calculated values. The program will also plot the individual events and filtered coda windows.
The principle for calculation is the standard coda Q method, whereby a coda window is bandpass filtered, an envelope fitted and the coda Q at the corresponding frequency calculated. The envelope is calculated RMS value of the filtered signal using a 5 cycle window. The program used here is the one described in Havskov et al. . The program can only operate in connection with the SEISAN format S-files. The program can use all waveform file types accepted by SEISAN and there can be more than one waveform file in the S-file. The program will also take advantage of the SEISAN database structure.