What happens underground when a missile or meteor hits

Techniques that enable researchers to simulate high-speed missile and meteor impacts into soil and sand have been developed for use in the lab. The techniques allow the researchers to watch what happens underground close-up, in super slow motion. They report that materials like soil and sand actually get stronger when they are struck harder. The research may ultimately lead to better control of earth-penetrating missiles designed to destroy deeply buried targets such as enemy bunkers or weapons stockpiles.