## 3 Experimental Results  
Figure 5 shows morphological characteristics of a typical experimental impact crater in granite, in which a central depression, crater rim, stuck spall piece, circumferential fracture, and radial cracks are identified. Figure 6 lists experimental impact craters of all the granite targets except shot no. 9. As shown in Figure 6, the local damage created by impact cratering was within the surfaces of the granite targets. All the craters showed approximately circular depressions within highly crushed target material in the center of the crater. The rims of the craters were irregular and non-circular in shape, which was caused by fragment spalling from the target. Several visible radial cracks with different lengths were located along the crater rim. On the surfaces of some targets, visible circumferential fractures could be observed outside the craters (shot No. 12 in Figure 6l), and the initial spall pieces were still stuck within the crater (shot No. 3 in Figure 6c). A three-dimensional (3D) laser scanner with a spatial resolution of 0.1 mm was employed to capture the morphologies and the dimensions of the craters. The high-precision 3D digital elevation models (3D-DEMs) of all the impact craters were restructured based on the scanning data, which contain the 3D spatial coordinate data of the impact craters. Figure 7 shows the three different views of a typical 3D-DEM of the impact crater morphology of shot No. 10, in which the crater depth from the original impact surface is identified by a color card. In Figure 7c, the approximately circular depression is identified with a yellow dashed line. The 3D-DEMs of the impact craters were handled to obtain precise crater parameters. Eighteen individual sections through the deepest point of an impact crater were produced, and the sections were spaced 10\({}^{\circ}\) from each other as shown in Figure 7a. Figure 8 illustrates the typical diagrammatic transect of the crater, in which the dimensions of the crater are identified. The crater diameter is the average of diameters of all 18 sections of the crater. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline
**Shot** & **Projectile** & \(\rho_{P}\) & \(m_{P}\) & \(l\) & \(d\) & _l/d_ & \(u\) & \(E_{k}\) & **Yaw Angle** & **Target** \\
**No. ** & **Type** & **(g/cm\({}^{3}\))** & **(g)** & **(cm)** & **(cm)** & **(km/s)** & **(k)** & **(\({}^{\circ}\))** & **No. ** \\ \hline
1 & TC4 & 4.44 & 39.33 & 3.666 & 1.833 & 2.00 & 1.95 & 74.78 & 4.3 & T26 \\
2 & TC4 & 4.44 & 39.30 & 3.662 & 1.831 & 2.00 & 2.33 & 106.76 & 4.5 & T01 \\
3 & TC4 & 4.44 & 39.37 & 3.664 & 1.830 & 2.00 & 3.15 & 195.13 & 6.7 & T13 \\
4 & TC4 & 4.44 & 39.35 & 3.664 & 1.833 & 2.00 & 3.55 & 247.83 & 8.2 & T02 \\
5 & TC4 & 4.44 & 39.30 & 3.664 & 1.831 & 2.00 & 3.99 & 313.07 & 0.8 & T32 \\
6 & 30 CrMnSiA & 7.81 & 39.58 & 3.053 & 1.521 & 2.01 & 1.94 & 74.43 & 24.5 & T24 \\
7 & 30 CrMnSiA & 7.81 & 39.76 & 3.047 & 1.521 & 2.00 & 2.43 & 116.77 & 3.8 & T20 \\
8 & 30 CrMnSiA & 7.81 & 39.78 & 3.047 & 1.521 & 2.00 & 3.06 & 185.17 & 0.1 & T19 \\
9 & 30 CrMnSiA & 7.81 & 39.49 & 3.049 & 1.522 & 2.00 & 3.48 & 239.48 & 0.0 & T04 \\
10 & 30 CrMnSiA & 7.81 & 39.78 & 3.047 & 1.522 & 2.00 & 3.91 & 302.32 & 13.8 & T30 \\
11 & 93 W & 17.78 & 40.48 & 2.338 & 1.162 & 2.01 & 1.91 & 73.42 & 32.8 & T22 \\
12 & 93 W & 17.78 & 40.46 & 2.327 & 1.161 & 2.00 & 2.51 & 126.79 & 11.9 & T35 \\
13 & 93 W & 17.78 & 40.34 Figure 5: Morphological characteristics of a typical experimental impact crater in granite (Shot No. 9). Figure 6: _Cont._  
Figure 6: Experimental impact craters of the granite targets: (**a**) Shot No. 1; (**b**) Shot No. 2; (**c**) Shot No. 3; (**d**) Shot No. 4; (**e**) Shot No. 5; (**f**) Shot No. 6; (**g**) Shot No. 7; (**h**) Shot No. 8; (**i**) Shot No. 10; (**j**) Shot No. 11; (**k**) Shot No. 12; (**l**) Shot No. 13; (**m**) Shot No. 14; (**n**) Shot No. 15.