On another note, I was looking at how the ice in the melange (between the and the Eastern ice shelf) was breaking up recently and I noticed how the red wedge near #8 in the image below has been developing over the past year. To make a long story short, I began to see it as a part of a much larger multi-year pattern which I will try to sketch out. There is a lot to unpack here so bear with me.
What I am calling the "Escalator" is a series of ice wedges that form in the "Fracture Zone" between the fast moving and slow moving areas of Thwaites ice shelf. The wedges (or "steps" in the analogy) are formed from the faster moving shelf that breaks away from the slower moving shelf at the shear margin.
The rest of the faster ice does not display this behavior. Most of the faster ice is in the calving zone where transverse (East-West) rifts form with separation of about a kilometer. Those long trips of ice eventually break into more square shaped tabular icebergs that form the bulk of the Tongue. Another portion of the faster ice calves at a front to the West.
The wedges are larger, 2-5 km in size, and they don't appear to fracture. The mechanism of their formation is a bit of a mystery, but I assume that they undergo some amount of compression before they break away from the slower ice, giving them atypical strength and thickness that makes them more durable than the surrounding icebergs.
I have tentatively identified and numbered these wedges in the picture below. The last two are still in formation so I am simply speculating on how they might emerge. The choice of numbering is not arbitrary, since #1 is the first wedge that can be identified in the current Tongue. Any previous wedges have since floated off (although the current tip of the Tongue may be the back end of an earlier wedge.)
This 5+ year GIF of the Tongue (
https://twitter.com/kevpluck/status/1228472054430781440) can help give a better picture of what may have led to the current structure and it deserves more analysis. The calving of the current Cork from the Eastern Ice Shelf in 2014 and a massive calving East of the Fracture Zone in 2016 which makes up most of the current Melange have resulted in the Tongue being pushed to the West. Before 2011 the Tongue was still connected to the Eastern Ice Shelf and it calved from an angular front which can still be seen in the pattern of the icebergs at the end of the Tongue.
The Western push from about 2015 to 1019 created the stair-step shape of the Escalator. It also exposed more of the Northern faces of the wedges which caused them to push on more of the melange. Most of the wedges can be associated with rifts in the melange (shown in red) where the points of the wedges have pushed apart the ice and even broken larger icebergs that they came in contact with. Two of the wedges (#3 and #5) have pushed icebergs in front of them which are indirectly pushing on the cork. The Western movement of the Tongue also resulted in it colliding with the underwater peak that has stripped off many of its icebergs.
Since the Cork now appears to be loose, it is assumed that the melange will eventually move off behind it. If the Tongue is no longer pushed as far Westward (no new hangups in the Melange) then the new wedges could continue in more of a straight line and the width of the Tongue could be restored to at least part of its former glory. However, the Western calving front will probably never be a part of the Tongue again. Of course, the Shear Zone could be causing permanent damage and that part of the Tongue may also join the calving front.
Another reason to track these wedges is that they are becoming proportionally a larger and larger part of the Tongue. In particular, #4 and #5 may comprise the entire width of the Tongue at some point, as the ice to their West gets stripped off. It is hard to so how such a reduced Tongue could hold together if the sea ice were to retreat.
I expect to keep studying this and hope to glean more details as I go along and I am willing to answer questions or make clarifications.