I think I found two work-arounds (that are probably not overly elegant, so if anyone has a better solution please let me know):
- For some reason the boundary of the first circle is affected by MAP_FRAME_PEN, therefore that can be changed (it will however lead to a thin border around the figure):
$gmt6 subplot begin 2x1 -Fs10c -Blrtb --MAP_FRAME_PEN=0.25p
- Introduce the flag to plot focal mechanisms and then just fill the table up with zeros:
$gmt6 coupe -Aa$minlon/44.3/$maxlon/45.4/1000/0/${max_depth}f -R$minlon/$maxlon/0/$max_depth -JX15/-4 -Sa -Fsc -W.25p -Ctemp_depth.cpt << END
15.6 45.2 60 0 0 0 0 0.3c
16 45.3 50 0 0 0 0 0.5c
18 45.5 20 0 0 0 0 0.2c
END
