Based on overflights and web camera views, HVO reported that fissure segment D from Kilauea's 21 July fissure eruption continued to feed perched lava ponds within a lava flow that frequently overflowed its channel edges during 12-18 December. An overflight on 13 December revealed that flows from the Thanksgiving Eve Breakout (TEB) were limited to breakouts at the base of the shield and were not active past 800 m from the source. Lava spattered and overturned in Pond 1 and overflowed the rim. On 16 December, a 4-5-m-high hornito at the summit of the TEB shield was active. On 17 December, lava from the TEB was about 1.1 km SE from fissure D and fume puffed from the top of the shield about every 15-20 minutes when visible. During 17-18 December, crust overturned in a new lava pond that had formed from a seep on the E side of Pond 3, and lava in the pond overflowed the margins. A few small earthquakes were located beneath the summit, and along the upper and lower E rift zones and S-flank fault.

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)