HVO reported that the W vent on the inner NW wall of Kilauea's Halema`uma`u Crater continued to supply the lava lake during 14-20 April. Lava flowed at a low rate from the main vent into the lake through crusted-over channels and submerged inlets. The depth of the lake was about 226-227 m and lava continued to circulate in the W part, though the active area continued to shrink; the E half of the lake remained solidified. Lava sometimes overflowed the margins of the lake. The sulfur dioxide emission rate was 950 tons/day on 14 April. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

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)