Page "Impact crater" Paragraph 23

Most material ejected from the crater is deposited within a few crater radii, but a small fraction may travel large distances at high velocity, and in large impacts it may exceed escape velocity and leave the impacted planet or moon entirely.

The majority of the fastest material is ejected from close to the center of impact, and the slowest material is ejected close to the rim at low velocities to form an overturned coherent flap of ejecta immediately outside the rim.

As ejecta escapes from the growing crater, it forms an expanding curtain in the shape of an inverted cone ; the trajectory of individual particles within the curtain is thought to be largely ballistic.