I am trying to calculate a simple model of free air anomaly using the gmt talwani3d by placing cylinders 0.05km high at 0.15km and 0.1km below the surface of a 10km x 10km flat surface. In the description of the 3D model table, I have written the z level and density contrast in the header for the two segments, but how do I specify the height of cylinders?
Can someone provide a suitable sample model description?