HVO reported that lava effusion intermittently continued at a vent in the lower W wall of Kilauea’s Halema`uma`u Crater during 21-28 December. Effusion paused for a period during 21-22, and sulfur dioxide emissions were 130 tonnes per day during the pause. Strong volcanic tremor began to be recorded at 1930 on 22 December and by 2000 lava again effused from the vent into the rejuvenated a portion of the lake. The lake overflowed and fed substantial lava flows that traveled SE over older crusted parts of the lake all day on 23 December until around midnight. Lava oozed out along the E margins of the lake during 24-25 December, including onto the lowermost down-dropped block from the 2018 caldera collapse, indicating a continuing supply of lava beneath the lake’s crust. The sulfur dioxide emission rate was about 5,300 tonnes per day on 24 December, much higher than during the pause. The surface of the lava lake had begun crusting over on 25 December and by 26 December lava had again ceased erupting from the vent. An area of the lake, 50 m in diameter, to the N of the vent remained molten on 27 December. The sulfur dioxide emission rate was 125 tonnes per day during the pause. Lava again erupted from the vent later that day, beginning at 1930. The lake was incandescent around the vent and lava overflowed the margins, feeding substantial lava flows to the N and S. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

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)