An inner wall 300 meters in diameter protected the heart of the settlement. (scientificamerican.com)
It can grow up to 2.5 meter in diameter although 0.5 meter examples are much more common. (xcalak.info)
Models by Christopher F. Chyba, then at the NASA Ames Research Center, and his colleagues proposed in 1993 that the asteroid was a few tens of meters in diameter and that it exploded several kilometers above the ground. (scientificamerican.com)