HVO reported that two lava lakes at Kilauea were active during 18-24 May. The level of the summit lava lake remained mostly stable deep in the vent inset within the E wall of Halema'uma'u Crater. Lava from a vent above the south side cascaded down into the lake. A gas plume from the vent drifted SW and likely deposited very small amounts of ash nearby. At Pu'u 'O'o crater, lava mostly from a vent near the W edge of the perched lava lake in the center of the crater floor continued to fill the lake. The lake level fluctuated and occasionally overflowed the edges or flowed through rim breaches, sending lava onto the Pu'u 'O'o crater floor. The rim of the perched lava lake was elevated several meters higher than the surrounding crater floor, which was 52 m below the E crater rim on 11 May. On 20 May a small lobe of lava visible in the web camera appeared on the W edge of the crater floor. The (preliminary) sulfur dioxide emission rate from all east rift zone sources was 800 tonnes/day on 20 May; the emission rates were slowly increasing.

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)