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.

T obs

Measured total-field magnitude at the station in nanotesla.

T reg

Regional (IGRF/main-field) magnitude at the station in nanotesla.

Total-field magnetic anomaly in nanotesla: the difference between the observed total-field magnitude and the regional (main-field) magnitude at the same location. 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]

Delta T

Total-field anomaly in nanotesla.

• 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.

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