Airy Isostatic Residual

The Isostatic processing tool applies a modified USGS algorithm to calculate the Airy isostatic regional field and residual gravity from a topographic grid.

The extension calculates the depth to the Moho (the "root") based on the topographic grid, terrain density, Moho density contrast, and the depth of sea-level compensation. It then calculates the 3D gravity response of that root at sea level, extending out to a radius of 166.7 km. To generate a complete Airy regional model, this output must be combined with a solution that extends beyond the 166.7 km limit.