Based on observations during helicopter overflights, visual observations from HVO and National Park Service (NPS) crews, and web camera views, HVO reported that during 2-8 April lava flow activity from Kilauea's Thanksgiving Eve Breakout (TEB) shield was mostly concentrated at the E Waikupanaha, W Waikupanaha, and Ki ocean entries. Spattering and small steam explosions were intermittently reported. Occasionally, incandescence from a skylight adjacent to the TEB vents and from breakouts along the lava-tube system was noted. Diffuse incandescence was seen on the web camera at Pu'u 'O'o crater during 2-4 and 7-8 April.

During the reporting period, Kilauea summit earthquakes were located beneath Halema`uma`u Crater, beneath the summit to the S and W, along the S-flank faults, and along the SW and E rift zones. The eruption from the vent in Halema'uma'u Crater continued to produce brown or white ash plumes that drifted mainly SW. During most nights incandescence was seen at the base of the plume and incandescent fragments were ejected from the vent. Based on pilot observations, the Washington VAAC reported that the plumes rose to altitudes of 3.4-3.8 km (11,200-12,500 ft) a.s.l. on 5 and 7 April. Seismic tremor was elevated.

Sulfur dioxide emission rates from the summit area have been elevated at 2-4 times background values since early January. The emission rate fluctuated between 480-800 tonnes per day during 2-7 April, compared to a background rate of 150-200 tonnes per day. At Pu'u 'O'o crater the emission rate was 1,300 tonnes on 5 April.

According to a news report, the Hawaii County Civil Defense issued a health advisory on 7 April for those living downwind of Halema'uma'u and Pu'u 'O'o craters. Residents of specified areas were then advised by the State Department of Health to evacuate because of projected dangerous level of sulfur dioxide. Residents of other areas were put on alert.

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.

Sources: US Geological Survey Hawaiian Volcano Observatory (HVO), Washington Volcanic Ash Advisory Center (VAAC), Honolulu Advertiser