During 9-15 September, HVO reported that lava flowed SE from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system, reaching the Waikupanaha ocean entry. Weak, sporadic explosions from the ocean entry were seen on 10 September. Occasional thermal anomalies detected in satellite images and visual observations revealed active surface lava flows.

The vent in Halema'uma'u crater continued to produce a diffuse white plume that drifted mainly SW. The plume briefly turned brown on 9 September from a rockfall. Small amounts of ash were retrieved from collection bins placed near the plume. Incandescence from small openings in the floor of the vent, about 200 m below the Halema'uma'u crater floor, was visible at night with varying intensity. During the night from 12 to13 September, spattering from the opening was seen on the web camera. The sulfur dioxide emission rate at the summit remained elevated; 900 tonnes per day was measured on 11 September. The 2003-2007 average rate was 140 tonnes per day.

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)