= Ridge-push force in a plate model
{title2=$F\simeq\rho_mg\alpha\Delta T a^2/6$}
The <ridge-push force in a plate model> is the depth <integral> of the horizontal <pressure> difference between hot and cold compensated columns. To leading order, the old plate's linear excess <density> gives $F=g\int_0^a s\delta\rho(s)\,ds=\rho_mg\alpha\Delta T a^2/6$. Here $s$ is depth below the old seafloor. Retaining the geometrical contribution from its lowered surface adds $g(\rho_m-\rho_w)h^2/2$ within the linear-density model. <Force> per ridge length has units $\mathrm{N\,m^{-1}}$, distinct from <stress>.
Back to article page
