[meteorite-list] Meteor Crater Shape and Entry Angle

[GeoZay at aol.com]

>>What can probably be agreed is  that an impactor with an 
entry angle of 45* degrees could produce a round  crater. Meaning of 
course that Meteor Crater, since it's not perfectly round  as evidenced 
by the "bulges" in the NW and SE corners, must have been  produced by an 
impactor with a trajectory much shallower than 45 degrees.  Logically.<<

I don't know, but I wonder if the shape of the terrain  upon 
impact(hills/gulleys etc) or perhaps a varied pattern of rock strength  underground could 
have had some influence to the craters shape?
GeoZay