Report on Kilauea (United States) — 6 January-12 January 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 6 January-12 January 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 6 January-12 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 vents on a cone on the inner NW wall of Kilauea’s Halema`uma`u Crater continued to feed a growing perched lava lake during 6-12 January. Lava flowed through a crusted channel into the lake during most of the week. A dome fountain of upwelled lava at the partially submerged inlet was 5 m tall early on 6 January. Dome fountaining had weakened early on 7 January, giving way to spattering at the top of the vent and the formation of a second cone. Dome fountaining was possibly visible again on 8 January. The lake was perched at least 1-2 m above its narrow edges, though late on 10 January the stagnant, eastern part of the lake had subsided and was 3-4 m shallower. Overall the lake had deepened just 2 m by 11 January, reaching 196 m, and the lake volume was estimated at more than 27 million cubic meters.
An island of cooler, solidified lava and the 11 smaller islands were relatively stationary in the E part of the lake. The dimensions of the largest island remained unchanged (250 m long and 135 m wide), though on 8 January the W end was 9 m above the lake’s surface and the high point was 23 m above the lake, suggesting that the island was rising. Sulfur dioxide emissions were 2,700 and 2,300 tonnes/day on 7 and 10 January, respectively.
Geologic Background. Kilauea, which overlaps the E flank of the massive Mauna Loa shield volcano, has been Hawaii's most active volcano during historical time. Eruptions are prominent in Polynesian legends; written documentation extending back to only 1820 records frequent summit and flank lava flow eruptions that were interspersed with periods of long-term lava lake activity that lasted until 1924 at Halemaumau crater, within the summit caldera. The 3 x 5 km caldera was formed in several stages about 1500 years ago and during the 18th century; eruptions have also originated from the lengthy East and SW rift zones, which extend to the sea on both sides of the volcano. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 km2, destroying nearly 200 houses and adding new coastline to the island.