Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 28 June-4 July 2023
Managing Editor: Sally Sennert
Please cite this report as:
Global Volcanism Program, 2023. Report on Kīlauea (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 28 June-4 July 2023. Smithsonian Institution and US Geological Survey. https://volcano.si.edu/showreport.cfm?gvpvar=GVP.WVAR20230628-332010
On 30 June HVO stated that Kīlauea was no longer erupting. Lava supply to the lake ceased on 19 June and sulfur dioxide emissions had decreased to near pre-eruption background levels. Seismicity was also low. The Volcano Alert Level was lowered to Advisory (the second level on a four-level scale) and the Aviation Color Code was lowered to Yellow (the second color on a four-color scale). The report noted that gradual inflation was detected at summit tiltmeters during 19-30 June. Incandescence from previously erupted lava was visible in overnight webcam images during 29-30 June; the lava continued to cool.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Geological Summary. Kīlauea overlaps the E flank of the massive Mauna Loa shield volcano in the Island of Hawaiʻi. 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 Halemaʻumaʻu 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.