HVO reported that two lava lakes at Kilauea were active during 20-26 July. The level of the summit lava lake fluctuated deep in the 150-m-diameter vent inset within the E wall of Halema'uma'u Crater and circulated with various patterns. Spattering occurred at locations along the edge of the lake. Periodic measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby. At Pu'u 'O'o, lava from vents near the NE edge of the perched lava lake in the center of the crater floor continued to fill the circulating lake. The perched lake and crater floor continued to be uplifted and cracks on the doming crater floor were observed. Minor lava activity was noted in the Puka Nui and MLK pits, smaller craters to the W of the main Pu'u 'O'o crater. Based on several measurements throughout July, the crater floor was uplifted about 0.5-1 m per day.

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)