Report on Kilauea (United States) — 6 June-12 June 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 6 June-12 June 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, 6 June-12 June 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 at Overlook Crater within Halema`uma`u Crater continued during 7-12 June. 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 where the fast-moving flow entered the ocean in the Kapoho Bay area. Minor lava activity at Fissures 16/18 was occasionally noted.
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; the floor had subsided at least 100 m during the previous few weeks, and by 12 June the lowest point was 300 m below the crater rim. Steam plumes rose from areas in the crater as well as from circumferential cracks adjacent to the crater.
Summit explosions occurred almost daily. Explosions at 1607 and 0244 on 6 and 8 June, respectively, each produced an ash plume that rose 3 km (10,000 ft) a.s.l. An explosion was recorded at 0448 on 9 June. Two explosions, the second larger than the first, were recorded at 0046 and 0443 on 11 June. An ash-poor explosion occurred at 0152 on 12 June. A pattern of an increasing number of earthquakes, an explosion, and then a drop-off of seismicity immediately afterwards had emerged during the past few weeks and continued.
A total of 12 rockfalls in Pu'u 'O'o Crater were recorded between 1031 and 1056 on 8 June, following a M 3.2 earthquake at the summit. A red dust plume was visible around 1050 but dissipated quickly.
Fountaining at Fissue 8 was stable, though by 10 June three closely spaced fountains were active within the 35-m-high spatter cone. The heights of the fountains varied, but rose no higher than 70 m. Pele's hair and other volcanic glass from the fountaining fell within Leilani Estates. The fountains continued to feed the fast-moving lava flow that traveled NE, and then SE around Kapoho Crater, and into the ocean. The width of the channel varied from 100-300 m along its length. Periodic overflows sometimes sent small flows down the sides of the channel. Lava entered the ocean at Kapoho Bay, building a lava delta that by 11 June was just over 100 hectares in area. A plume of laze rose from the entry points. An area of strong thermal upwelling in the ocean around 920 m out from the visible lava-delta front was visible beginning on 7 June, suggesting lava flowing on the ocean floor. According to a news report, the Hawaii County Mayor noted that by 8 June lava flows had destroyed over 600 homes.
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.