During 16-22 January HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. The gas plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas. During 15-16 January rocks fell into and disrupted the lake surface. The lake level was 35 m below the Halema'uma'u crater floor on 16 January and 27 m below the floor on 19 January.

At Pu'u 'O'o Crater, glow emanated from spatter cones on the SE part of the crater floor, from a spatter cone at the NW edge of the floor, and from a circulating lava lake on the NE part of the floor. Lava flows were active in a 1-km-wide area that stretched from near the base of the pali to the coast. Web cameras recorded steam plumes from lava sporadically entering the ocean at multiple locations. Lava levels remained mostly high in the crater; several lava flows from multiple vents were active on the crater floor. The lava lake was perched several meters above the crater rim and sporadically issued lava that flowed outside the crater and onto the E flank of the cone.

Geological Summary. Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)