HVO reported that during 3-9 September, lava flowed SE through a lava tube system from underneath Kilauea's Thanksgiving Eve Breakout (TEB) and rootless shield complex, reaching the Waikupanaha ocean entry and one further to the E. On 5 September, geologists saw multiple surface flows during an aerial observation: four on the coastal plain, and a large 'a'a flow and a small pahoehoe flow in the abandoned Royal Gardens subdivision.

The vent in Halema'uma'u crater continued to produce a predominantly white plume with minor ash content that drifted mainly SW. The plume was occasionally tinged brown in association with small local earthquakes. Weak night-time incandescence was intermittently seen at the base of the plume, and rock impact sounds were heard in the vicinity of the crater. The sample collection bin contained tephra, Pele's hair, Pele's tears, and a variously shaped glass fragments. On 5 September, scientists saw the surface of a sloshing lava lake, 50 m in diameter, about 100 m below the vent rim while hovering over the vent in a helicopter. A second view revealed a roiling pond with multiple bursting bubbles that changed into a central upwelling circulation pattern. The level of the lake dropped slightly before the cycle restarted.

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)