Fig. 2
From: Effect of projectile shape and interior structure on crater size in strength regime
Typical crater profiles resulting from impact of a closed copper tube on (upper) porous gypsum target (shot # 1101-2) and (lower) basalt target (shot # 1031-3). The surface diameter, Ds, the inner (pit) diameter, Di, and the depth, d, are defined as the diameter at the target surface, the diameter at the pit, and the distance from the surface to the deepest part of the crater, respectively. Note that the vertical scale is exaggerated