Use this geological calculation for a transparent first-pass interpretation of measured rock, soil, fluid, well, stratigraphic, isotopic, geophysical, or seismic data under an explicitly selected model.

Decompacted thickness (m)

Backstripped-unit decompacted thickness in metres.

Sediment density (kg/m^3)

Mean sediment density in kilograms per cubic metre.

Paleo-water depth (m)

Paleo-water depth at deposition in metres (positive down).

Sea-level change (m)

Sea level at deposition relative to present in metres; default 0.

Mantle density (kg/m^3)

Mantle (asthenosphere) density in kilograms per cubic metre; default 3330.

Water density (kg/m^3)

Paleo-water density in kilograms per cubic metre; default 1000.

Water-loaded backstripped tectonic subsidence (Steckler & Watts 1978) with a eustatic correction: Y = S(rho_m - rho_s)/(rho_m - rho_w) - Wd + dSL * rho_w/(rho_m - rho_w). Positive sea-level change means past sea level was higher than present. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Tectonic subsidence (m)

Backstripped tectonic subsidence in metres.

• Gravity, magnetic, flexural, and subsidence interpretations are non-unique and depend on datum, corrections, density or susceptibility contrasts, regional removal, geometry, elastic assumptions, and noise. A corrected anomaly is not a unique subsurface model.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Compare independent measurements and models, retain units and analytical metadata, propagate uncertainty, and validate interpretations against logs, cores, maps, laboratory data, or field observations.

• Air Loaded Subsidence Calculator

  Air-loaded tectonic subsidence with the water column replaced by air (zero load): Y = S(rho_m - rho_s)/rho_m - Wd.

• Water Loaded Subsidence Calculator

  Water-loaded tectonic subsidence after removing the sediment load and replacing it with water: Y = S(rho_m - rho_s)/(rho_m - rho_w) - Wd.

• Subsidence Rate Calculator

  Average tectonic-plus-loaded subsidence rate over an interval: amount divided by duration.