During 10-16 August HVO reported that Kilauea's summit lava lake was mostly crusted, but lava, possibly from a source higher on the SE wall, occasionally flowed over the surface. Small rockfalls from the vent walls were frequent, and the gas plume from the vent continued to deposit variable amounts of ash and occasionally fresh spatter nearby. During an overflight on 11 August, scientists observed an E-W trench in the deepest part of the cavity. Lava was upwelling from the E end and flowing W. During 14-15 August hot and possibly spattering vents were visible on the W part of the cavity floor.

At the E-rift zone, lava continued to trickle onto Pu'u 'O'o's collapsed crater floor and some spattering occurred from various sources the floor. The W-flank vents remained active and fed an elongated perched lava pond that extended to the SW, and also a small flow which advanced a short distance N. Small overflows or breaches from the elongated lake were occasionally active on the N side. During the 11 August overflight, scientists noted that the activity was less vigorous; the two channels that continued to feed the perched lake were crusted over and the W-flank vents were no longer spattering. The pond rims were higher and the pond was narrower, lava flows from the base of the pond were active on the N and W sides of the pond, and the S rim of the pond appeared to be slowly migrating S. The crater floor subsided a small amount on 15 August.

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)