OK there is a bunch of activity in the fault line across from Indonesia to Fiji. Most of this is a subduction zone where the Indo-Australian plate is bending and going under the plate above it. A bunch of the quakes lately have been more about the bending than anything, not really it sliding under the other plate. And parts of the zone are the other way, the pacific plate or Asian plate is sliding under (or the I-A plate is slidding over and bending the pacific plate.) Where the cross happens is stuck and instead of going past each other there is a slow motion crash happening.
But what happens if the bend breaks., the part that was sliding under drops away and the whole place becomes a train wreck. Some of the quakes recently don’t look like the typical release of a stuck point and sliding but rather something happening at the bend. These quakes, like the New Ireland quake today are on the side of the line away from the subducted part. The stress here is the bending, where i-a plate is not yet under the pacific plate. But the quake is too deep to be on the part being stretched by the bend, it’s at the part being compressed but the crust resists crushing, it’s much better at resisting compression stress especially at that depth where it’s already compressed from both directions. So it looks more like a fracture and could be an early indicator of the subducted part being broken off rather than bent under and subducted.
Just something else for me to check if other quakes in the area are also of this same signature.