During 17-23 February, HVO reported an active lava surface about 200 m below a vent in the floor of Kilauea's Halema'uma'u crater. The lava surface circulated and occasionally spattered, and both rose and drained through holes in the cavity floor. Bursting bubbles and low lava fountains were also noted. A plume from the vent drifted mainly SW, dropping small amounts of ash downwind. Measurements on 18 February indicated that the sulfur dioxide emission rate at the summit remained elevated at 600 tonnes per day. The 2003-2007 average rate was 140 tonnes per day.

Lava from beneath the Thanksgiving Eve Breakout (TEB) and rootless shield complex flowed over 3 km SE through a lava tube system before breaking out onto the surface. Thermal anomalies detected by satellite and visual observations revealed active lava flows on the W side of the TEB flow field, on the pali, and on the coastal plain. Incandescence was sometimes seen from a vent low on the S wall of Pu'u 'O'o crater.

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)