Oxidation formula (Subsidence Overlay)

The amount of subsidence due to oxidation is calculated by the following formula:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle S_O = d_{gw,y} * a_{y} - d_{ct} * b - c}

where

• Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle S_O} is the subsidence due to oxidation.
• Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle d_{gw,y}} is the calculated ground water depth for year y.
• $a_{y}$ is the calculated a parameter value for the current year $y$.
• $d_{ct}$ is the clay thickness of the terrain, defined by CLAY_THICKNESS
• $b$ is the b parameter value, defined by PARAMETER B
• $c$ is the c parameter value, defined by PARAMETER C

This formula was provided by experts, who have derived this formula empirically.