Deep seismicity in the Himalaya: metamorphic or tectonic connection?

There is a particular cluster of earthquakes at about 70 km beneath the Himalaya and southern Tibet, which has been re-assessed in our recent paper. It can have a metamorphic origin from dehydration reactions, but it also connects to a major basement fault zone that cuts across the orogen at depth.
The ultimate figure from Michailos et al. (2021)