So, stumpled a short while ago over Galan. I try to catch up...

So, stumpled a short while ago over Galan. I try to catch up with the whole lot of superb information provided in this thread, but of course didn`t get all of it, so sorry, if this question was already asked or if it is a dump question (no geo).
So, if the level of brine found (if found) in H2 is several hundred meters deeper than in H1, wouldn`t this ask for some impermeable barrier somewhere between this to holes? If the brine could flow relatively freely (without barrier) between this two holes it should gather at depth above the "down thrown block" and there shouldn`t be much brine left near H1 (except it is very very slowly draining from Galaxy, nice thought).
If this barrier exists, we basically should have two brine containing structures at different depths.
Any ideas how to find such a barrier?
The csamt images as such don`t seem to be too reliable, they indicate brine where there is none (upto now at least)