During 29 December-4 January, HVO reported that activity at Kilauea continued from the summit caldera and the east rift zone. At the summit caldera, the level of the lava-pool surface in the deep pit within Halema'uma'u crater circulated and remained mostly stable at approximately 120 m below the crater floor, periodically rising several meters higher. Nighttime incandescence was visible from the Jaggar Museum on the NW caldera rim. A plume from the vent that drifted mainly SW deposited ash and fresh spatter nearby.

At the east rift zone, lava that broke out of the Quarry tube onto the surface, at a saddle between two rootless shields at around the 610 m elevation, continued to advance in two branches. The lava flow at the lowest elevation advanced E beyond Kalapana by 3 January. Incandescence from a small spatter cone on the north-central part of Pu'u 'O'o crater floor continued. Lava from that cone flowed SE, NE, and W. Lava from a second spatter cone, located on the NW edge of the crater, was active on the crater floor. Weak incandescence was also visible from a small, fume-producing vent in the E wall of the crater, and from other various areas on the crater floor.

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)