27.4 Program QSTAT

This program also use the codaq.area to make statistics etc. After running CODAQ, codaq.area contains all individule coda Q determinations. The program first finds all the stations which has contributed to the calculations and makes an output file qstat.stat with station codes and station coordiantes (require STATION0.HYP) so a map can be made with the 'good' stations. If a station is not found in STATION0.HYP, the lat-lon will be 0.0 0.0 in output file. Then a plot is made with Q as a function of distance for each frequecy and a histogram is made with the the distribution of Q values for each frequency. The latter is intended to be illustrate the spred in the Q values and is useful when comparing Q from different areas. Note that the number of values for each frequency are not absolute, but scaled to fit the plot. The number of values for each frequency is indicated on the plot.

Figure 27.3: The top plot shows Coda Q as a function of epicentral distance and the bottom plot shows the distribution of individual Q-values for each frequency. n is the number of Q-values for each frequency