tail end first impact of intact a/c ?
I would concur with those posters theorising that the VS broke off in its entirety on impact and I would add: of a by and large intact a/c.
Looking at the VS photo's, I dare to argue that the a/c impacted more or less level flight, but at a very high AOA, making the very end of the tail section hit the water first, crunching the tail section upwards and in the process damaging the lower-edge of the rudder and unsettling the VS attachment. Subsequent impact of the main, more forward a/c sections would then arrest the forward movement of the VS to the point that it separates from the tail-section alltogether.
Just theorising on what material is available at present.