Using EPIMAP, it is possible to select out events in a polygon when plotting the codaQ midpoints (or other epicentres). It is then possible to calculate the average Q in that area using the program CODAQ_POLYGON. The input polygon coordinates are assumed to be present in file epimap.cor, the one created by EPIMAP when selecting in a polygon. The codaQ values in the midpoints are supposed to be present in file codaq.area and no questions are asked. File coda1.out is also used as input and must be present.
The data in the polygon file is written out in a file POLYGON.MAP so it can be plotted again with EPIMAP. The POLYGON.MAP file is appended to so if CODAQ_AREA is used several times with different polygon areas, they will all be stored in POLYGON.MAP read for plotting with EPIMAP. It is up to the user to ensure the POLYGON.MAP is empty if a new series of polygons are stored.
codaq_polygon Frequencies 1.00 2.00 4.00 8.00 16.00 Number of points in polygon: 11 Number of Q-midpoints within polygon: 165 q0= 197.8 sd 6.0 qalpha= 0.73 sd 0.02 Accumulated polygon coordinates in POLYGON.MAP
How to calculate coda Q in polygon areas
Calculate coda Q in large area of interest.
indexCoda Q in a polygon Plot all the midpoints between station end events with EPIMAP. The input epicentre file is codaq.area.nor which is output from CODAQ.
Do the following for each polygon area:
With EPIMAP, use polygon function to select an area. Terminate EPIMAP.
Run codaq_polygon to calculate coda Q for that area, the polygon outline is stored in file
POLYGON.MAP for later plotting.
After e.g. 5 runs, the 5 areas are stored in POLYGON.MAP and the Q-relations have been printed out.