Based on visual observations from HVO and National Park Service (NPS) crews as well as web camera views, HVO reported that during 12-18 March lava flow activity from Kilauea's Thanksgiving Eve Breakout (TEB) shield was concentrated at rootless satellitic shields to the SE, in and near the Royal Gardens subdivision, and at ocean entries. During 12-13 March, lava flows entered the ocean at multiple locations on the Waikupanaha delta and at a new location 100 m E. A breakout from the E margin near the access road split into two lobes, surrounded and destroyed existing structures and covered the access road, and entered a nearby kipuka. On 14 March, lava entered the ocean at two primary Waikupanaha delta locations; the W delta was 600 m wide. An overflight revealed that the Kalalua flow (from the rootless shield complex to the E and SE of the TEB shield) advanced 240 m since 6 March. Lobes from the E-margin lava flows advanced SE into the kipuka and S of the access road, and entered the ocean during 14-15 March. Breakout lava flows were visible inland of the Waikupanaha and new ocean entires, at the base of Royal Gardens, and near the top of the pali. During 15-18 March, lava flows entered the ocean at multiple locations on the Waikupanaha delta and at a new location, 200 m W of the viewing area, named the Ki entry. On 17 March, breakouts and burned vegetation were visible within 1 km of the ocean entries.

During the reporting period, Kilauea summit earthquakes were located E of Halema'uma'u crater, along the S-flank faults, and along the SW and lower E rift zones. Sometime during 10-12 March, a new gas vent appeared just above the base of the E wall of Halema'uma'u crater. During 14-18 March, incandescence from the gas vent originated from a spot about 30 m wide within the rubble at the base of the E crater wall. Cracking rocks, possibly due to the heat, were heard by scientists at the Halema'uma'u overlook. On 17 March, the area of incandescence appeared slightly enlarged with a new area higher on the crater wall and to the N.

Sulfur dioxide emission rates from the summit area have been elevated at 2-4 times background values since early January. The emission rate abruptly increased on 12 March and fluctuated between 1,600-2,500 tonnes per day during 12-16 March, compared to a background rate of 150-200 tonnes per day. On 16 March, emission rates reached 2,500 tonnes per day, the highest recorded at Kilauea's summit since measurements began in 1979.

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)