Halema‘uma‘u lava lake, Kīlauea summit eruption—May 13, 2021

USGS Hawaiian Volcano Observatory geologists observed fluid lava on the surface of the lava lake in Halema‘uma‘u, at the summit of Kīlauea, while monitoring the eruption on May 13. Two areas of ponded lava exhibited foundering, during which more-dense solidified crust sinks into the lava lake and is replaced by less-dense liquid lava from below. This photo shows the southern ponded area foundering at approximately 2:15 p.m. HST. USGS image by K. Mulliken.