Surface particle motions excited by a low velocity normal impact into a granular medium

• Published in: Icarus (New York, N.Y. 1962) Vol. 390; p. 115301
• Main Authors: Neiderbach, Max, Suo, Bingcheng, Wright, Esteban, Quillen, A.C., Lee, Mokin, Miklavcic, Peter, Askari, Hesam, Sánchez, Paul
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.01.2023
• Subjects: Asteroids; Cratering; Impact processes; Impact processes; Cratering; Asteroids
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2022.115301

In laboratory experiments, high speed videos are used to detect and track mm-size surface particle motions caused by a low velocity normal impact into sand. Outside the final crater radius and prior to the landing of the ejecta curtain, particle displacements are measured via particle tracking velocimetry and with a cross-correlation method. Surface particles rebound and are also permanently displaced with both peak and permanent displacements rapidly decaying as a function of distance from the crater center. The surface begins to move before most of the ejecta curtain has landed, but continues to move after the subsurface seismic pulse has decayed. Ray angles for surface and subsurface velocities are similar to those described by a Maxwell’s Z-model. This implies that the flow field outside the crater excavation region is a continuation of the crater excavation flow. The ratio of final particle displacement to crater radius resembles that measured for other impact craters. •High speed videos are used to study surface motions caused by impacts in sand.•Surface displacement decays with a power law form.•The flow field outside the crater is a continuation of the crater excavation flow.•Final displacement divided by crater radius resembles that of other impact craters.