2026-04-18
Subterranean drift is the primary horizontal instability of the groundline relative to the ground, as ecotectonic drift is for the emergence.
The subsurface layer (157 words) undergoes uniform drift of about seventy metres a year. The vertical branches of the subsurface drift together, which is the primary evidence for it being a single layer. Even this drift makes fixed, permanent connections between the subsurface and the ground impossible.
The lesser deep (104 words) drifts differently in different places. A place can reappear kilometres away the next week, while neighbouring ones haven’t moved. No physical explanation for this behavior is known.
As for the greater deep (87 words), it is unknown whether it drifts. All who venture there (215 words) die.[Opinion]