Report on Kilauea (United States) — 15 August-21 August 2018
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 15 August-21 August 2018
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2018. Report on Kilauea (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 15 August-21 August 2018. Smithsonian Institution and US Geological Survey.
19.421°N, 155.287°W; summit elev. 1222 m
All times are local (unless otherwise noted)
On 17 August HVO lowered the Alert Level for Kilauea to Watch (the Aviation Color Code remained at Orange), noting reduced activity over the previous several days. Specifically, no collapse events had occurred at the summit since 2 August, lava ceased flowing in the channel from the Fissure 8 cone on 6 August, seismicity and ground deformation at the summit were negligible, and the combined rate of sulfur dioxide emission from the summit and the LERZ were lower than any time since late 2007. The small lava pond in Fissure 8 had crusted over by 17 August, with no observed incandescence. Lava continued to ooze into the ocean at a few areas, causing minimal laze plumes. During an overflight on 20 August gas jets ejected spatter from a small incandescent area deep within the Fissure 8 cone.
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.