PSMECA with -Sx|y option

Dear GMT developers and users,

I am going to plot a focal mechanism using parameters on the attachment (Table A2.png, solution no.61). My understanding, based on the documentation here:, I have to use psmeca with -Sx|y option. But, my attempts have had no luck so far.

Based on the information in Table A2, my data is:
118.8 -3.1 13 4*10e+23 73 68 344 0 253 22 25

The script I tried:
grep -v “#” Fitch1969.txt | psmeca -J -R -Sx2 -O -Groyalblue -K -T >> $psFile
grep -v “#” Fitch1969.txt | psmeca -J -R -Sy2 -O -Groyalblue -K -T >> $psFile

I use GMT version 5.4.5

The intended focal mechanism is shown in the attachment (focal_mechanism_sol.61.png).
I appreciate your help.



Hi Rino,

I think you could try to use the -Sp option because you have partial information on the moment tensor, but you also would need to calculate the strikes and dips of the two planes from the poles to the planes.


Hi Eric,

Thanks for the clue.