Page "Impact crater" Paragraph 17

In physical terms, a supersonic shock wave initiates from the point of contact.

As this shock wave expands, it decelerates and compresses the impactor, and it accelerates and compresses the target.

Stress levels within the shock wave far exceed the strength of solid materials ; consequently, both the impactor and the target close to the impact site are irreversibly damaged.

Many crystalline minerals can be transformed into higher-density phases by shock waves ; for example, the common mineral quartz can be transformed into the higher-pressure forms coesite and stishovite.

Many other shock-related changes take place within both impactor and target as the shock wave passes through, and some of these changes can be used as diagnostic tools to determine whether particular geological features were produced by impact cratering.