Is this what you want?
gmt begin insar_plot png
gmt set MAP_FRAME_TYPE inside
gmt subplot begin 3x3 -Fs3i -A
gmt basemap -R0/10/0/10 -c
gmt basemap -R0/10/0/10 -c -Bwsen
gmt basemap -R0/10/0/10 -c -Bwsen
gmt subplot end
gmt end show
