Report on Kilauea (United States) — 30 December-5 January 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
30 December-5 January 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2020. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 30 December-5 January 2021. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
HVO reported that lava effusion from a vent on the inner NW wall of Kilauea’s Halema`uma`u Crater continued to feed a growing lava lake during 30 December-5 January. A cone had formed over the remaining active vent, which was one of three that had opened at the beginning of the eruption. Lava sometimes spattered from vents at the top of a cone and flowed down into the lake through a crusted-over channel; during 2-5 January a dome fountain was visible near the lake’s margin, formed by upwelling of lava as in entered the lake at a partially submerged inlet.
The lake deepened from 181 m on 30 December to 191 m by 4 January, and the lake volume was an estimated 26 million cubic meters by 4 January. An island of cooler, solidified lava continued to float around on the lava lake’s surface, and by 4 January the island’s surface was 1-2 m above the surface of the lava lake. Over the week the island was joined by less than a dozen other small islands of cooled and solidified material that also moved around, though they mostly remained in the eastern part of the lake. The lava lake was also becoming perched as overflows of lava onto the narrow edge formed around the lake’s margins continued to build a levee; by 3 January the lake was perched about 1 m above the margin. Sulfur dioxide emissions fluctuated between 3,000 and 6,500 tonnes/day. Seismicity remained elevated but stable.
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.