A computation of the fluid pressure change caused by uplift of a sealed porous rock suggests that a typical brine-filled clastic rock with a normal fluid-pressure gradient (FPG) at about 6,000 ft (1,830 m) would experience a reduction of FPG of about 0.1 per 1,000 ft (300 m) of uplift (and unloading) if the rock remained sealed and mechanically unchanged. The effects of temperature and external pressure are included and finite rock, grain, and fluid compressibilities are used. Under the same conditions increased burial would produce an increase of FPG of 0.1 per 1,000 ft (300 m).

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