Seeking Advice: Discrepancies in Selecting Earthquakes Using gmt project and pscoupe

Hello GMT experts,

I am reaching out for your guidance on a matter related to selecting earthquakes in subduction zones using GMT. Specifically, I have been using the project command for this purpose, but I recently discovered discrepancies when compared to an alternative approach using the pscoupe command, as suggested by a coworker.

To provide a clearer picture, I have prepared a MWE as follows:

gmt project eq.txt -h1 -C143/37 -A299 -L-300/1500 -W-120/120 -S -Q -V -Fpz > proj_azi.txt
gmt psbasemap -Jx0.01c/-0.01c -R0/3000/0/700 -Bx500 -By100 -V -K >
gmt pscoupe eq.txt -J -R -Fsd4p -Gred -Ab143/37/299/1800/+d90+w120+z0/700 -V -K -O >>
gmt psxy proj_azi.txt -J -R -Sc2p -Gblack -W0.1p -O >>
gmt psconvert -Tg -A

Despite employing the same initial dataset and utilizing identical parameters, the selection of earthquakes differs between the project and pscoupe approaches. This has led me to question whether I may have made an error or if this issue is related to how the two commands handle projections.

I have come across this previous post discussing this same topic, but I am hopeful that someone with extensive expertise can provide further insights and help me understand the correct approach.

Thank you in advance,

eq.txt (42.6 KB)

1 Like