That looks like a low speed hit ... i wud say between 20-30mph .. Reason I believe is cause newer cars are designed that way to take more impact from the front in order to save the passengers in the car ahead of the crashing vehicle. In other words, REAR enforcement is made stronger to take more of the hit and Front enforcement is made lighter to take more impact ... (keep in mind trunks are empty and hollow so it would be easier to harm passengers in the first car) ... like wise on the front we have airbags and engine drop down mounts for passenger safety ...while not too much to offer from the rear end.
REASON WHY AIRBAGS DIDN'T DEPLOY: If you notice the cars front bumper is pretty intact ... no major damage .. air bag sensors are right besides those little square caps you see .. Sensors never felt the impact to deploy the airbags ...
I had a similar accident last year ... I drive a 3 inch dropped civic and i rammed in to the back of a Land cruiser ... my hood scrapped exactly like that and the land cruisers towing hatchet stabbed my radiator . As everything was above the front bumpers ... no airbags deployed ...