Interesting -- This is screaming new variant to me.
It reminds me of the old computer game "Populous".
Seismic in its pure sense is solely a game of normal Dip with a topological shift (split/join) each turn per player. No adding or removing of canals.
However, this thread now begs for a variant like say, "Terraform" in which you can do seismic shifts or other changes.
Possible orders:
Sink: Add a canal. Now fleets may pass thru this space and to all spaces connected to it.
Fill: Remove a canal.
Flood: Turn a sunken (land, with canal) zone into a sea zone. Armies may no longer land here.
Drain: Turn a sea zone into a land zone (with canal).
Build: Add an SC (neutral)
Burn: Remove an SC (neutral)
Migrate: Move an SC to adjacent province
Incite: Cause an owned but unoccupied SC to go neutral
Bribe: Cause a neutral SC to become owned.
Many other possibilities.
I re-wrote (and need to improve) rules for the formation/deletion of canals/straits. That way, you can run canals through Rome or StP if the right conditions arise.
Adam