HVO lowered the Volcano Alert Level for Kilauea to Advisory and the Aviation Color Code to Yellow on 5 June, noting that the fissure eruption that had occurred in a remote area along the Southwest Rift Zone on 3 June was unlikely to restart. Tremor, degassing, and incandescence associated with the fissure vents had substantially decreased. A sulfur dioxide emission rate of 5,500 tonnes per day (t/d) was measured at the eruption site on 4 June, well above background levels (100 t/d or less). Sulfur dioxide emissions decreased to 400 t/d on 6 June and likely continued to decline over subsequent days. Lava flows only covered about 350,000 square meters (0.35 square kilometers). Incandescence from the flow field was visible in webcam images, but decreased daily and was no longer visible by 10 June.

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.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)