Lava forms a “dome fountain” at the inlet to the lava lake in Halema'uma'u crater January 2-3, 2021.
Lava from the western vent cascades beneath roofed vertical channels to enter the lava lake at an inlet that has become partially submerged.
The result is a rolling upwelling of lava near the inlet called a “dome fountain.” Dome fountains have been observed during eruptions at Mauna Ulu and Pu‘u ‘Ō‘ō.
Dome fountains can occur when lava rapidly emerges from a constricted vent or fissure onto the surface or, as in this case, beneath the surface of a lava lake.
The feature resembles, in part, a bubbling water fountain.
The height of the dome fountain was estimated to be about 5 m (16 ft) with an estimated width of 10 m (33 ft).