That photo is excellent. Note the little white rectangular strips, tabs around the periphery - which when taken with the major ' folds" and the ' grey" color looks to me more like insulation blanket(s) on the aft side of the aft bulkhead rather than bent aluminum. ON the outer ' rim" of the " [ bulkhead or blanket] " I also note the impression of rivet heads or buttons. This also leads me to infer what is seen is a blanket- since with that amount of deformation, rivets would be sheared or torn from the surrounding formed or extruded " ring " structure. [ e.g a circular "stringer" ]
In either case, it does look like a major downword force on the empenage/tail bending the whole mess upwords **perhaps* due to a nose high position at impact.
