The Hawaiian Volcano Observatory (HVO) reported that the eruption that began at 0220 on 23 December continued during 24-30 December from vents located at the SW margin of Halema’uma’u Crater within Kilauea’s Kaluapele summit caldera. Fissures opened at 0220 on 23 December producing lava fountains and lava flows that advanced across the Halema’uma’u Crater floor and overflowed onto the down-dropped block area to the E. The eruption had paused by 1600 on the 23rd, but at 0800 on 24 December several of the vents began erupting slow-moving lava flows. Lava fountaining was visible and intensified at 1100. Breakouts of lava were visible on the surface of the lava lake on the crater floor as it continued to circulate. Vigorous lava fountains rose 75 m high from a main vent during 1430-1615. A significant amount of tephra from the fountaining during 23-25 December accumulated on the closed portion of Crater Rim Drive, producing deep drifts of cinder over and alongside the road. Lava flows continued to spread across the crater floor on 25 December, covering lava from the first day of the eruption, or just under 2.6 square kilometers. Lava flows on the crater floor were a few meters deep. Minutes before 1100 on 25 December the lava fountains decreased, and at 1100 lava drained back into the vent. At around the same time summit tiltmeters began recording a change from deflation to inflation and seismic tremor decreased. Sulfur dioxide emissions remain elevated, with a gas plume rising above the caldera, but the vigor of the outgassing notably decreased. Lava flows on the crater floor stagnated.

Minor lava effusion began again around 0800 on 26 December from the SW vents. Scientists in the field reported numerous rockfalls from the crater walls. Small lava flows traveled short distances from the vent during 26-27 December, causing an elevated “pad” of lava about 140 x 170 m in size and elevated about 2-3 m above the darker surrounding lava lake. The vents produced spatter and low-level fountaining. More vigorous fountaining began at around 1800 on 27 December with periodic fountain bursts rising 10-15 m above the vents. Sulfur dioxide emissions were elevated, with a gas plume rising above the caldera, but outgassing vigor was greatly reduced compared to the periods of higher lava fountaining in previous days. Deflation began in the S part of the caldera at around 1300 and tiltmeter data showed the inflation had flattened beneath Halema’uma’u Crater by 1500.

Fountaining from the more south of two active vents increased and became more continuous at 1715 on 28 December. Lava was ejected 20-30 m high. By 1800 the advancing lava flows had covered about 20 percent of the crater floor. Tremor levels had been gradually increasing over the past two days but were relatively low compared to earlier periods of vigorous fountaining. Sustained lava fountaining 30-40 m high continued during 29-31 December. A large fan of lava covered the SW part of the crater floor and advanced towards the central part of the floor. Sulfur dioxide emissions drifted SW.

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)