During 7-13 December, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater, remaining below the inner ledge (75 m below the crater floor). Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and fresh spatter nearby.

Incandescence was visible along the E and W edges of the Pu'u 'O'o crater floor, along the 21 September fissure on the SE flank of Pu'u 'O'o cone, and from a skylight on the lava tube. Lava continues to erupt into the perched pond formed on 6 December. Pahoehoe flows, fed through lava tubes from the fissure, continued to be active about 6.8 km SE of Pu'u 'O'o based on intermittent views from satellite. Analysis of 10-12 December satellite images suggested that lava had reached the coast and was flowing into the ocean. During 11-12 December incandescence was observed from small spatter cones on the E and S edges of the Pu'u 'O'o crater floor; short lava flows issued from the E edge of the crater floor on 12 December.

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)