The summit lava lake has dropped significantly during the past week and is now again 50 m below the rim of the pit crater inside Halema'uma'u.
After a few days of repeated small overflows at the end of April until early May, the lake had been perched for a few days at its highest level, started to drop after 10 May, first slowly, then more rapidly. During the past days, it has stabilized at approx. 50 m depth.
The process was accompanied by rapid deflation. Where the lava drained is not easy to say with certainty. But on one hand, no significantly new or increased activity has been observed at the Pu'u 'O'O vent on the active Eastern Rift zone; on the other hand, increased earthquake activity has occurred under the SW rift zone during the same time as the deflation and lava lake draining. The latter suggests that a part of the lava lake migrated into new underground fractures beneath that area.
Whether or not this could lead to a new eruption on the SW rift zone is speculation at the moment. The SW rift zone saw its last eruption in 1974.
In September last year, Mount Ontake in central Japan erupted unexpectedly, killing dozens of hikers.