I'm not sure Columbia has an exploration focus. Most big Universities don't. Almost all exploration programs are in states where O&G industry exists.
I'll be starting in UT this fall and besides Stanford, I think it's the best option. They have a good variety of courses in seismic interpretation, processing, and related courses which could be of interest, such as rock physics, reservoir geomechanics, geology courses (sedimentology, structural, etc), basin analysis, subsurface mapping and workstations, etc. Other good options are U. of Oklahoma, U. of Houston, CSM. The thing is as you said, in CSM they tend to focus more on processing, which can be really difficult, depending on your skills and what you like.
Another thing to look for is faculty, some good universities or relatively good universities don't have enough faculty dedicated to seismic exploration. That's why I think both Stanford and UT are the best overall.
You get to choose what you study and how focused you will be in it. You can get courses on each stage of seismic exploration, or specialized in interpretation, or imaging, etc.
Check other Universities where O&G exploration is big and they should have good programs. Maybe it's not a good university but that specific department is good.