On 21 March HVO reported that Kīlauea was no longer erupting. The lava lake in Halemaʻumaʻu Crater was no longer being supplied as of 7 March based on lava lake levels and crater floor observations. Sulfur dioxide emissions had decreased to near pre-eruption background levels. The Volcano Alert Level was lowered to Advisory (the second lowest level on a four-level scale) and the Aviation Color Code was lowered to Yellow (the second lowest color on a four-color scale).

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

Geological Summary. Kīlauea overlaps the E flank of the massive Mauna Loa shield volcano in the Island of Hawaiʻi. 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 Halemaʻumaʻu 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.