Howdy,

I have seen the term used in mining, but in a general sense it is the deposition of altered materials in the actual fault zone. The dictionary I look at does not disciminate between oceanic faults versus land faults, so my terminology may be wrong for the Solomon area. Here are the definitions and the parent site---excellent resource for all who are learning, I would say. It came from my study of gold mines, originally.

Glen

Gouge====
a. A layer of soft, earthy or clayey, fault-comminuted rock material along the wall of a vein, so named because a miner can "gouge" it out to facilitate the mining of the vein itself. Syn: selvage; pug. See also: gouge clay; hulk. b. The clay or clayey material along a fault or shear zone. Also called clay gouge. See: fault gougec. To work a mine without plan or system.
Source: Dictionary of Mining, Mineral, and Related Terms

Fault Gouge====
A layer of hardened clay lining a fault plane, commonly showing grooves and striae indicating the direction of most recent movement. Syn: fault casing
Source: Dictionary of Mining, Mineral, and Related Terms

• Dictionary-Parent site