During 15-21 April, 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 and Kupapa'u ocean entries. Occasional explosions occurred from the Waikupanaha ocean entry. Surface flows were present on the coastal plain and at the base of the pali. The vent in Halema'uma'u crater continued to produce a white plume occasionally tinged brown that drifted mainly SW. Incandescence was intermittently seen from the vent, and sounds resembling rushing gas or rockfalls were sometimes heard in the vicinity of the crater. Pele's hair, tiny glass spheres, and ash were frequently retrieved from collection bins placed near the plume. The sulfur dioxide emission rate at the summit was elevated, reaching 700 tonnes per day on 15 April; 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)