Following Impact: The Collapse of the Crater
Alamo Impact Crater Formation

Normal faults are generated throughout the crater from the impact force. Fault blocks form along the crater walls, breaking off and sliding back into the crater following impact. Rocks around the crater rim fill in much of the crater as it collapses. Furthermore, resurge waves deposit large amounts of rock fragments in and around the crater. It is common for the crater to almost completely refill and subsequently be buried!

Resurge 1 Resurge 2