Report on Kilauea (United States) — 18 July-24 July 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
18 July-24 July 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Kilauea (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 July-24 July 2018. 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 the eruption at Kilauea’s Lower East Rift Zone (LERZ) and within Halema`uma`u Crater continued during 18-24 July. Lava fountaining and spatter was concentrated at Fissure 8, feeding lava flows that spread through Leilani Estates and Lanipuna Gardens subdivisions, and built out the coastline at multiple ocean entries.
Inward slumping of the crater rim and walls of Halema`uma`u continued, adjusting from the withdrawal of magma and subsidence of the summit area. Explosions from collapse events occurred almost daily, often followed by a surge in activity at Fissure 8. Sulfur dioxide emissions from the summit were very low.
Fountaining at Fissure 8 continued, producing Pele's hair and other volcanic glass that fell within Leilani Estates. The fountains continued to feed the lava flow that traveled NE, and then SSE, W of Kapoho Crater. Channel overflows on 18 July destroyed structures in the Leilani Subdivision. The channelized ‘a’a flow was incandescent along its entire length as it flowed towards the ocean. It generated plumes of laze (a corrosive steam plume mixed with hydrochloric acid and fine volcanic glass particles) at several points along a broad 6-km-wide flow front, though the main entry area was at Ahalanui, a few hundred meters E of the flow edge which was 175 m NE of Isaac Hale Park (by 24 July). HVO noted that the lava delta was unstable as it has been built out as far as 800 m from the original coastline on unconsolidated lava fragments and sand.
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.