Small earthquake swarms were recorded at Kilauea on 30 December 2022 and 2 January 2023, with heightened seismicity in between those dates. Increased seismicity and changes in the pattern of deformation began to be recorded during the morning of 5 January. At around 1500 both the rate of deformation and seismicity dramatically increased indicating magma moving towards the surface; at 1520 HVO raised the Volcano Alert Level to Watch (the second highest level on a four-level scale) and the Aviation Color Code to Orange (the second highest color on a four-color scale).

Incandescence seen in webcam images at 1634 on 5 January indicated that an eruption began in Halema’uma’u Crater, prompting HVO to raise the Volcano Alert Level to Warning (the highest level on a four-level scale) and the Aviation Color Code to Red (the highest color on a four-color scale). Vents opened in the E central portion of the crater floor and produced multiple lava fountains and flows. Fountain bursts ejected lava as high as 50 m during the initial phase of activity, though in general fountaining was consistently 10 m high. By 1930 lava had covered most of the crater floor (an area of about 120 hectares) to a depth of 10 m. A higher-elevation island that formed during the initial phase of the December 2020 eruption remained exposed (and appeared darker in images) along with a ring of older lava around the lava lake that was active prior to December 2022. Overnight during 5-6 January the lava fountains became less vigorous, rising to 5 m, and lava effusion slowed. By 0815 on 6 January HVO lowered the Volcano Alert Level to Watch and the Aviation Color Code to Orange because the initial high effusion rates were declining and there was no threat of significant volcanic ash outside of the closed area within?Hawai’i Volcanoes National Park. The sulfur dioxide emission rate was about 12,500 tonnes per day. Lava continued to erupt from the vents during 6-8 January, though the footprint of the active area had shrunk, which has been common during the early stages of recent eruptions within Halema’uma’u. By 9 January only one dominant fountain was visible that continued to be active at least through 10 January.

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)