Mean-zero: belts rise, the rest subsides, total volume conserved.
Noise belts
Plates
Convergent margins build orogens, divergent margins rift.
Ocean–continent gives a trench and an arc offset inboard — the signature of
subduction, not the mechanism: nothing is consumed and margins never migrate.
Crust
Fraction of a thickness change that shows at the surface. 1 = rigid
crust, no rebound. True Airy is 0.152 — erode a kilometre off a range and it
rebounds 850 m, which is why ranges persist.
Mountain displacement baked straight into the crust wherever the
pressure is high — present at once rather than grown by uplift over thousands of steps.
Impacts
Bowl and central peak excavated, the same volume laid back down as
rim and an r⁻³ ejecta blanket. Ejecta lands as sediment. A fresh basin is a closed
drainage sink — watch the rim breach and the floor fill.
Erosion
Water
Rock
Fluids
2D fluid on the same cubed-sphere atlas — № 02's PIC/FLIP reusing
this experiment's halo and metric. Not built yet.